However, rolling a D20 is a lot of fun, which makes me not want to replace it with something like 3d6.

Fun is subjective, but I personally really enjoy rolling a big dice pool. 4 fire firearms, 3 for dex, 2 for equipment bonus, 4 for the fate blessing, 4 for the gun being magically perfected, 3 for aiming, that's approximately Get Fucked dice to throw on the table.

it has a lot of assumptions deeply baked into the rules. You need the adventuring day, to rewrite all the powers, or sharply limit party composition, or it falls apart.

The adventuring day is a big one. TBH I’ve never seen a ttrpg without it.

Any whitewolf rpg. Fate. Gurps. Don't rest your head. Unknown armies. Countless indie RPGs. Many games that aren't close relatives of D&D don't have a central model of "you have a limited amount of resources to get through the day".

I recently started a game of Vampire: The Requiem. One of the guys had only played D&D before, and it kind of blew his mind that he can just do his iconic stuff whenever he wants. He was going to punch a bouncer and we were like "Why don't you just use your mesmerize?", and he was like "I forgot I don't have to save that"

There are massive amounts of fan content for DnD out there and easy to find, if you don’t want to write your own. There are whole ttrpgs that are practically modded DnD but tweaked for a specific setting.

You can also use an actual generic system like Fate or GURPS. Both of those have a ton of fan content as well. This is not a unique strength of D&D.

Hard disagree on social conflict. DnD is full of mechanics for that.

Please share. From what I recall, the system is limited to something like "Roll persuasion vs a DC, and that determines how big of a favor they'll do for you", or similar for intimidation.

Imagine a scenario where the players encounter a group of goons blocking the road. If they want to get in a fight, D&D has a ton of rules. Movement, to-hit and damage, armor, saves. If they want to talk through it, the rules are comparably thread-bare. There's no social HP.

Other systems give you more. I'm pretty sure a lot of PbtA games have social moves. There's also Monster Hearts, which I never played because you need a particular kind of group for that one.

Side note: because of how D&D's stats work, you end up with a lot of characters are mechanically bad at socializing, or underperform at their prescribed roles. You have to work against the system to get some concepts. The whole idea of "multiple ability dependent" is a D&D-ism that's just not in every system. If you want to play a wise cracking dashing axe-man in Fate, for example, you can just do that. You don't need to worry about how you can get both strength and charisma, nor about if you can just reflavor Hexblade because you don't really want the rest of Warlock.

Meta game currency is something DMs usually add in from my experience, although DnD does have inspiration points as a kinda weak form. Succeed at a cost is something I usually see DMs add in, but I have seen other ttrpgs with that more baked into the rules.

Inspiration is kind of store-brand fate points, yes. You can easily add more to it, as well as bring succeed-at-a-cost into D&D. But the argument is more about how D&D provides little.

You pick from a list. If you want to play a game about creating your own spells, it’s going to provide little guidance. Yeah that’s fair. If you have an example of a game with a good “make your own spells” system I’m curious.

Mage: The Awakening (2e) is the crunchy one that I know. The book provides a ton of examples, but even those are flexible. You add or lose dice based on adjusting the spell details, and potentially create a pool of fuck-up dice in exchange for more dramatic changes.

Unknown Armies is an old classic that has "random magick" as a thing any duke can pull off.

Fate is a generic system, so it really depends on which splatbook you're using, or what your table decides on. One game I ran had a "choose one: slow, dangerous, expensive" model for magic. The player can't picking "dangerous" and things got really exciting.

Also, most of the spells are about combat, with a handful about movement. Hard, hard disagree there. Off the top of my head: prestidigitation, minor illusion, friends, zone of truth, tiny hut, message, command, good berry, that one that lets you ask god a question…

I was curious so I'm looking at a spell list on a dnd wiki. A majority of spells are for combat, followed by spells that also have exploration uses (eg: fly, alarm), and then there's everything else. But you can't deny that a large chunk of the spells are explicitly about doing damage, or helping you do damage.

I spent too long on this post. Hopefully it was worth it! "People should play more RPGs, even if just to steal stuff to port into D&D" is one of my bugbears.

To give you another rec, which is often named as an intro to PbtA systems for dnd players: Dungeon World. It still borrows quite a few things from DnD (which are imo the worst parts of DW).

And as the other user wrote, reading other system can even be helpful just to steal stuff for your DnD group. PbtA (or one based on it) is one that imo every GM should've played, because it teaches so many important principles that are relevant in any systems you play - but in PbtA they are far more explicit (and well explained in the rulebooks).

I’m not sure what you mean about limiting party composition.

Oh I missed this earlier.

So one solution to the pain caused by the adventuring day is to let players rest more often. But some classes get way more powerful after a long rest than others, so that's a problem. A party of {fighter monk wizard} that gets a long rest after every fight is going to have a superstar wizard. One solution to that is only let the party consist of classes on the same rest cadence. Wizard, cleric, paladin, ranger are all long rest based. Fighter, rogue, monk, warlock are short rest.

This causes tension even in a base line game. It's very common for wizard players to whine about wanting a rest even when the rest of the party is good to go. You might say that's their fault for not rationing their powers, but I'd say it's their fault for playing a resource management game when they wanted to play a wizard game.

Removing the adventuring day and corresponding "you need to rest to recover resources" is really difficult in DND. But people want to remove it, even if not consciously, because it sucks unless you're aiming for a narrow range of game modes.