In a feeble attempt to move things back on topic:
Business Plan/Vision:
I hope this means removing the 5e art for the halfling.
Flavor/Lore:
I would also like to see even a few snippets per monster entry that suggest other ways outside of the lore to use the monster. Something that invites the Gamemaster to not necessarily strictly adhere to the MM lore for their own homebrews or games. You could even have entries that note things like, "In older editions of the game, kobolds were rat-doglike things that looked like this - [show picture in sidebar] - you may prefer to include these in your game too. Here are a few ways to incorporate these non-draconic kobolds into your game..."
Also, I personally favor a lot of the lore of 4e, and I am thankful that a lot was subtely incorporated into 5e, though 5e did make its own breaks with prior lore. (Moving Succubi/Incubi to NE was a pretty smart compromise between 1-3e and 4e lore, which itself stemmed from a desire to have the alignment make more sense with their nature/use.) But I would nevertheless like to see more of the old 4e lore, because it did some wonders for the game, such as giving a rhyme and reason for the different types of undead, distinguishing druidic magic from the divine magic of clerics, etc.
Mechanics:
Here I would invite WotC to re-examine the balance between (sub)classes on a short rest resource management and those (sub)classes on a long rest resource management. The balance relies on an assumed group tempo for encounters per day that does not necessarily reflex praxis, while short rest mechanic balance also makes those classes more DM-dependent.
I appreciate your inclusion of the Warlord on the list. Thank you. If the Warlord could fit comfortably on the Fighter chassis, I would not be opposed to it being a subclass of the Fighter. I simply think that the current Fighter chassis is a bit too damage-output-heavy for the Warlord class fantasy. Also I would add the Artificer to the list, though this may be something some would preserve for the inevitable 6e Eberron.
As I personal preference, I would also look at the druid, which has been a quiet dud with some imbalances between the Land vs. Moon paths, their respective interaction with the level 20 capstone (favoring the Moon path), and with the lack of scaling of shapeshifting forms. I would probably just say, "You pick the appearance of the animal, but when you wild shape, you select a scaling shapeshifting archetype with a particular function (e.g., guardian, predator, flyer, swarm, etc.) and possibly choose some abilities associated with each archetype."
Regarding the sorcerer? Who knows? Everyone seems to have different ideas on how to make the class meaningful now that nearly every class is a spontaneous caster. Which leads me to...
Since Arcana Unearthed/Evolved from Monte Cook's Malhavoc Press print had a similar quasi-vancian system (prepared spontaneous casting) and a universal magic system with a singular spell list, then I would also advocate looking at that system for inspiration on how a 6e could distinguish spellcasting classes more by flavor and playstyle while also streamlining the spell lists. If you are not familiar with how their spell system worked, I would be more than happy to provide a brief tutorial because it was incredibly neat and I wish that other games had adopted something similar.
I prefer minion rules but since some don't, I would suggest more modular rules.
Feats: I would possibly decouple feats from ASI, because sometimes players feel that ASI is too obligatory for efficiency before getting to pick cool things that feats permit. And for some classes, grabbing ASI is more necessary than others. Another downside, IMHO, of having feats being so heavy per feat is that this provides the Vuman with a lot
umpf in the early levels of the game that sees the greatest amount of play while leaving non-vumans without as much hit-the-ground-running customization options. So I would arguably look at ways that feats could be re-worked slightly.
Backgrounds: Decouple its associated Bond/Flaw/Ideal system, as this is something that should apply much more broadly than just your background. Why wouldn't your bonds, flaws, and ideals not also be associated with your species or class, for example, and not just your background?
Right now I am eying how PF2 handles multiclassing through its feat system. But I first want to see how the final form works in practice before making such a recommendation.
I don't necessarily think that lethality is as much of the issue as is the lack of cool things for monsters to do beyond being sacks of HP. I would bring back 4e monster design. PF2 will be adopting a similar approach where they want to give monsters more unique abilities.
