Warning, long post ahead!
You have a personal dislike of the druid wild-shape; that's why you proposed your changes. And your changes do nerf the class, which is part of the point of your changes.
I do dislike druid wild shape, but not because I don't like the concept, only the execution. But I am not trying to nerf the ability. Only bring it in line with what one would expect from a Cleric or Bard. It seems to me that many people who have had objections to my wild shape changes want the druid to be able to cast spells, have good physical stats, more HP, and combat options from their chosen wild shape forms. For me, that is too much. Additionally, in my first iterations of these changes, I had gone through the available wild shape options and averaged out their physical stats, speed, movement types, proficiencies, and special abilities. I was trying to create a "base" animal form that could then be upgraded or customized as you leveled up. My thought was that this would standardize wild shape while removing the need to use the Monster Manual. What I found was that it was too difficult and more complicated. So I abandoned Wild Shape entirely and tried to start from scratch. I thought about the fundamental role of the druid and the problems that wild shape was meant to resolve. What I came up with was that wild shape was meant to help with exploration. I used my awareness of the typical abilities that available beast forms granted (not considering combat abilities such as pack tactics or constrict), and utilized that as a basis for Wild Shape. I then considered how the Moon Druid uses Wild Shape differently for combat, and attempted to adjust my revamped wild shape to achieve the goal of a druid capable of competent melee fighting. It won't take the spotlight from the Fighter, Barbarian, or Paladin... but then even the Moon Druid eventually gets 9th level spells. So I don't know that a Moon Druid should be able to take the spotlight from those martial classes any more than a War Cleric or a Valor Bard.
And I mean that's cool, but not everyone shares your dislike of the class abilities. And it would be a real shame for some players in your game who want to play a druid to find out they can't play the class they wanted because the DM just didn't like it and so they have to play some altered form the DM came up with, or else play another class. (Have you put it up for a vote by your players? I'd be curious if more of them would prefer to play your version of the druid over the official version.)
Most of my homebrew material is mostly for theory-crafting. I very seldom get to playtest it because I tend to play and run in longterm campaigns rather than short-campaigns or one-shots. However, every player has a choice at my table when I run. I don't force anyone to play my version of anything, but I do make it available for them. Fun over rules all when I run a game, and if playing a standard druid is what will allow the player or group maximum enjoyment, that is what happens.
I generally favor light touches when it comes to house rules and changes to mechanics. And before I make a big change, I try to make sure it's not just my own personal dislike of something that is driving the change. Case-in-point, I really personally dislike multi-classing. But most other people don't agree with me, so I still allow my players to do it because I don't want to take the fun away from them.
I've personally reworked nearly every class and archetype. People use this hobby for different things. But I see the power balance a bit differently than most and think some abilities just outright don't seem fun. But as I said, it's mostly just theory crafting and I rarely get to playtest. And I have no problem being driven by my personal tastes regarding these things. I always consider what would make a class, ability, spell, or feat fun for me. But I don't force any such decisions on any of my players.
You started off by saying it was the difficulty of the class and the need to use the MM to reference beasts that prompted your changes. But of course other classes may also need to reference the MM. Rangers with their pets. Casters with their familiars. Wizards and bards with polymorph. Wizards (and others?) with conjure elementals. Etc. Additionally, most people I know don't find it too difficult to play druids or photocopy some monster block stats to keep with them for their wild-shape forms.
Yes, and I have worked to standardize these issues as well to avoid such things. I have reworked the rangers to standardize their beast companion so they don't need to look at the Monster Manual (which allows the ranger to craft whatever kind of creature they like out of the provided stat block. Want an owlbear companion? A Cthulu monster? All good as long as it mechanically functions based on its stats). Wizard familiars I'm less concerned with because of the limited choice there. I'm more concerned by Pact of the Chain Warlock familiars. But that is something I just have yet to tackle. And as for the spells... well... polymorph is something I also don't like. But I have no idea how to approach it that doesn't break the spell further. But with the conjuration spells, while the caster can request a certain type of creature, ultimately its the DM that chooses if the summoned creature is appropriate. And while the caster may command the creature, that doesn't necessarily mean that the player is privy to the creature's stats or acts for the creature. In the end, summoned creatures are DM controlled NPCs. At least that is my take.
Now it seems to me your real complaint is that you think druids are overpowered. None of your original four reasons for wanting to change wild-shape referenced their over-powered nature, but it has risen to the top of your arguments.
I don't think I have once stated any argument about druids being overpowered with Wild Shape. Difficulty standardizing the power level between different wild shapes, yes. Keeping in mind that the Druid is a full casters and asking if a full caster should have access to all that wild shape offers, yes. I don't think Wild Shape is over-powered or broken so much as problematic. But it is interesting to me that proposing such a drastic change to wild shape prompts so many cries of dissent. It seems almost at the level of being a sacred cow of D&D. So much has changed from 3e to 5e, so why is it that Wild Shape must remain so similar to its previous incarnation?
As far as your proposals specifically, I am not against the idea of making rules a little less complex and easier to understand and run. But I find your rules changes more complex, not less. It seems a lot easier to just say, "oh you turn into a bear? Here is your stat sheet. You are now this bear." That seems a lot easier than the various rules you proposed. (Also more fun, IMO. I'm not just an amorphous, abstract, wild-shape thing, and every wild-shape thing is the same with the same abilities. I am a bear! With its own unique traits.)
That's fair. Like I have said all along, this adjustment to wild shape is anti-simulationist. If you need to take on the stat block that WotC determined was a bear to feel like a bear, go for it. But to me, no stat block has been able to capture or define any particular creature, and so it makes no difference how you skin the stat block. I find having more freedom to skin things as I like and using a standardized framework for the mechanics is much more fun.
My apologies; I totally missed your changes to the Moon Druid Wild Shape at the bottom of the post (either due to the late hour or senility, not sure which
) That fixes most of my concerns about disincentivizing it. However it’s biggest concerns for me are the temp hit points and the fact that it does make druids more dependent on their physical stats.
Oke doke, lets see if I can address some of your concerns. ^_^
1) The temp hit points being equal to Druid level (instead of being a totally separate pool as it is now) means a druid gets knocked out of the fight pretty quickly; I know this is a complaint for some people, but it makes the Druid robust in support without being too powerful offensively. If needed, my Moon Druid can put up with three times the punishment of our paladin, but he can’t dish out the same kind of damage. He makes an excellent anchor for a front line temporarily and if a front line fighter goes down can fill in until the cleric can get them back up.
So here's my way of framing the Temp HP versus an HP pool. For one, in my version of Wild Shape a druid doesn't lose their armor or shield AC, and can choose Unarmored Defense if its higher. That means that they won't have the typical lower AC of their wild shape forms and thus would need less HP. Additionally, Temp HP avoids the issues presented by things like Power Word Kill, where if you take a form with fewer HP, you aren't necessarily going to be affected. Finally, the Moon Druid can still use a bonus action to sacrifice spell slots to heal. And since Moon Druids can't cast while in Wild Shape anyways, to hang onto those spell slots makes less sense. And if the Druid gets really desperate, they can drop Wild Shape, take the Dodge action, and jump into a new wild shape for some additional Temp HP. The Moon Druid is still going to have a lot of longevity in a fight.
2) being so much more heavily dependent on a Druid’s existing stats means that as others have said you have to be strong in not one or two abilities, but four (Strength, Dex, Con, and Wisdom). 5 or 10 extra hit points will only keep you in the fight for at most one extra round.
Eh... you might want to reread my adjustment again. Most combat abilities like AC, attack, and damage get modified by Wisdom for a Moon Druid while in wild shape. For other situations, they get advantage on Perception checks and can choose one other skill from Athletics, Acrobatics, Stealth, and Survival to gain advantage on. This allows Moon Druids to continue to be competent in battle.
For Druids that aren't Moon Druids, yes they are likely to have poor physical stats. But they gain advantage on up to two relevant exploration-linked skills to mitigate that, and they aren't meant to use their wild shape for combat. From my perspective, while their physical stats don't change, they have ways to address such weaknesses without making them sudden physical paragons based on their chosen wild shape.
3) finally, not a mechanical complaint so much as a complexity complaint - it feels far more complex to me, much like the way you have to keep track of spell buffs in 3e or Pathfinder. I’d have to keep a separate sheet to keep track of my wild form stuff (due to all the altered stats being based on the druid’s existing stats), instead of the way it is now, which is to flip open the monster manual and just read off of a short stat block. Actually, there’s an app on Android that keeps track of all of a druid’s Wild shape possibilities by CR and movement mode that even takes the Monster manual out of the equation.
So this is a concern to me, because I am definitely trying to reduce complexity. But I also don't understand what people are seeing as stat changes. Temp HP is pretty standard and can be acquired in many ways. You don't change your physical stats, except to gain advantage on 2 skills. You get new movement forms. Your new attack form is no different than acquiring a new weapon (non-Moon Druid) or Cantrip (Moon Druid). And your AC for Moon Druids either stays the same or increases to 10 + Dex + Wis (whichever is higher). To me, these are all changes that can be tracked on your character sheet. While there are some more bullet points compared to a Barbarian's Rage ability (which is what I used as my model for the adjusted Wild Shape), the kinds of changes are relatively similar.
Perhaps complexity is the wrong word to use in what I'm trying to address. Maybe the nature of PHB wild shape makes the changes too dramatic, since it really is just in essence a completely different character sheet outside of mental stats.
