The best way is to look at current hit points as your ability to soak up immediate trauma, and HD as representing the rest of your hp. Basically, you can only handle taking about half of your total resiliency's worth of damage in a short period of time, but if you rest up, you can get back into the action.
I probably have a radically different preferred way of doing hit points but that is far easier to houserule. It is pretty easy to revert back to even pre-3e. Just throw away the whole HD construct. Now that preference has nothing to do with metagaming and more to do with other preferences.
I don't think it's too much of stretch to say they can only pull these off occasionally and that they might be choosing the moment of when to do them. But it is more difficult to explain than the HD, and no optional rules are provided.
Being able to effectively only pull off certain maneuvers so many times a day has never been the issue. Choosing when you can pull those off is the issue.
I just go with it, and it works fairly well as an in-character choice.
Mechanically, however, Second Wind can be problematic because a fighter can just sit around for a few hours doing it repeatedly and recover all his hp (though not HD). I've house-ruled that a character can benefit from no more than 4 short rests per day, primarily to address Second Wind, but it also works for other things that might be problematic.. So far, we've never run up against a situation where we would exceed those 4, and it does fix the conceptual problem.
The problem you are dealing with here though is a game balance issue. It's not really a metagame issue. I agree it could be abused but I can deal with those sorts of issues and always have. Also, it doesn't really work as an in character choice for me.
You didn't mention Battle Master maneuvers, which are similar to Action Surge and Second Wind.
Probably because I'd just ban that whole construct right out of the gate. Not that many of my fighter players would think to choose it anyway.
You have a single pool of Superiority Dice you spend on the maneuvers which replenishes on a short rest, so at least it isn't by maneuver recharging. By the book, you don't have to declare using the maneuvers until you hit (or it otherwise comes up). That is simple to fix however. You just say the player has to declare what maneuver they are attempting, and if they fail to hit then the opportunity to complete the maneuver just didn't occur, and hence the full effort wasn't expended (so the die isn't lost). Battle Master's are masters of this stuff, so they know when not to overexert themselves. Of course, you could go hardcore and say the die is expended whether or not the maneuver succeeds, but I think that's unnecessary. The simpler method rarely changes the way the way the game goes (or balance) to any noticeable degree.
In fact, I've decided not worry about it and just let the player declare after success...but my player rarely remembers that and usually declares before taking the action anyway.
I agree with you that making the player declare before they hit is a no brainer. Same for the rogue. Still I'm probably more in the camp that prefers to have manuevers if they even exist activated by events not directly under the player's control but still reflective of the character's fighting ability.
Another potentially problematic one is the rogue's Sneak Attack, which you don't have to declare until after the attack hits (though based on other rules, I do believe the intent is that you do declare before you roll damage, thus not allowing you to see if an opponent dies before deciding to use Sneak Attack, so there isn't that particular problem) but you can only use 1/turn. However, when they fail on the first attack and get to try again on the second one, that's where it is weird.
One interpretation is to say that the rogue can spot when the opportunities are there to make a hit be a really good hit. You could say the player has to declare that their character is going for a Sneak Attack before the roll, which shouldn't change how things play out.
Another interpretation of why this is once a turn is that it takes more focus than you can consistently pull off when you are stabbing quickly. I can relate to that general sort of restriction from playing action video games. It really does take more focus than I can maintain to play "at my best" every moment. It doesn't work as well as the first, but works well in combination with the first.
Sneak Attack in 5e works against everything, so it needs to be interpreted a bit differently anyway.
I agree and in this case since it is every turn but only once in that turn it is fine. It takes a level of concentration that precludes it happening more than once in a few seconds period.
I don't worry about requiring a pre-declaration on this one. I assume the character is always trying to make the best hit they can (ie, they use Sneak Attack at the first opportunity--which my players actually do, so it works), and they just can't maintain the focus on every attack.
Any other interpretation besides yours is really nonsensical. I know people use feints etc.. but those aren't rolled attacks. An attack is a serious attempt to do damage.
Yeah, it's definitely unapologetically metagame. Ignoring it works perfectly fine.
Overall, 5e design seems to have embraced more metagaming than most D&D, but not really done what 4e did. Or at least when they borrowed ideas from 4e in those regards they attempted to tone it down so you could creatively interpret it (like I described above).
If you can work with the sorts of explanations I gave above, you can probably work with pretty much all of the metagame elements in 5e without a serious problem.
Actually you seem very reasonable and I really appreciate a serious answer to my question. I think though you may be talking me out of it. I know that is not your intention and I'm glad it works for you.
Probably one of the biggest things that bugs me is how learning cantrips works. You are limited to only ever knowing a small number of what are supposed to be the simplest spells, even when you can know everything else on your class list automatically (clerics/druids), or theoretically learn them all, including wish (wizards). Drives me crazy. My house rule is that prepared casters can use a spell preparation slot to prepare other cantrips (which means wizards can add them to their spellbook like any other spell). Prepared cantrips can still be cast at-will. It's not really a problem with casters who know a limited number of spells anyway, though I would allow them to switch a cantrip when they level up, since they can do so with spells of other levels.
One idea I've played with is having cantrips be first level spells. You cast the cantrip which lasts for so many hours and gives you the effective ability. Another is just getting rid of cantrips. I really feel like the original concept for the core classes is something I like. The wizard should be holding their powder. But that is again not a metagame taste but just a general taste on the class. But if you give the wizard one extra first level spell and then make all cantrips first level spells that when cast give you the ability for 8 hours you will maintain the vancian concept if that is your goal. Keep in mind though that things like dispel magic will cancel a cantrip spell immediately which I like. Cantrips also get more powerful which to me doesn't make sense. Instead just have persistent spells at varying levels the wizard can prepare if he so chooses. So the really good cantrip is a 4th level spell instead of a 1st level one.
This one bothers me so much from a suspension of disbelief perspective that if I'm playing a prepared caster in someone else's campaign I would actually be so bold as to request my house rule be in effect. I'm not sure I could stomach playing a wizard otherwise.
In practice, no one has ever used my house rule for that. Spell preparations are so precious that my players just haven't wanted to take up a slot with a cantrip, even though it would add an at-will spell to their complement.
It's always interesting to see what others view as intolerable. We all have our tastes and desired views on the game. Agree or disagree I can respect the concept.
I haven't looked at Pathfinder 2 yet. Too crunchy for me, though I'll probably at least scan the SRD to look at the design elements.
Well I haven't seen the game yet but I will definitely download the pdf. I'm leaning that way at this point. I think the core structure will be non-dissociative and each feat will then be in or out. When you have a system, it's easier to throw out individual items without otherwise wrecking the game. It's easier to put new ones in too.
Right this very second though I am working on a sci-fi campaign using a modestly houseruled N.E.W. Mostly I will just remove the limited use powers as options. Modify the underly flavor of luck (or drop it). I've been hankering to try something besides fantasy for a while but have yet to see a game that really tickled my fancy. I really liked the core of N.E.W. for that sort of game. I'll definitely add a lot of setting based fluff / skills / professions etc...
