More feats is much more interesting than extra attack (which is also granted in 3.5e).

You can also tell by her anorexic physique that she's no landchad. No fridge raiding happening here.

Depends on how strong the potion is. In 5e, healing is kinda weak, so bonus action makes sense. In PF2E, potions are stronger, so 2 actions (or more depending on what you got in hand) to draw and drink makes sense.

DND writes its rules to be as quick to read and apply to basic situations, but then becomes unwieldy in many if the non-standard cases because they didn't take the word count to fine tune the rules work as you necessarily would expect, and thus they become confusing.

Something like PF2E (while not perfect in clarity, but much better) has much more verbose rules, but they do a better job of making them apply to non-standard situations closer to how you expect more often.

I think that's kind of how contested rolls work in delta green. Whoever has the better stage of success wins (better stages are lower numbers), but if you both have the same stage of success, the one who has the higher number wins. It gives the edge to those with larger numbers in a skill, since they have more numbers that are higher than what the other person could get and still remain in that tier of success.

At that point, you lose a lot of verisimilitude, and that's pretty important to me.

You definitely can screw yourself a lot with uninformed choices, but they are less impactful per choice, and the base kit of classes are good enough that bad feat picks won't make you useless.

The biggest exception here is spell selection, shit spell selection can feel really bad, and there are a decent amount of "trap" spells (not that the spells are bad, but it's easy to misunderstand the intended purpose).

But if you have the tools that tell you how to make differently balanced encounters, it makes the job of balancing the game waaaay easier.

Are there any feats that are or can easily be flavored to basically setting yourself on fire to damage creature who touch or attack you?

Rock and Stone!

Also relevant to an all tree folk parry (maybe a couple halflings in the mix)

Pathfinder 2e in particular is very good at making combat feel cinematic and role-playee, where teamwork matters, so players interact with each other a lot more. Having a combat heavy system doesn't make it a bad system, it just means it's a good RPG system for heavy combat role-playing. It also allows the "g" part in "rpg" to be more present as well.