It doesn't, combat feels 90% the same but now you can get disarmed once in a blue moon.
But they improved the open world a lot, it feels very organic how you find quest now, it is just smoke and mirrors and it's not really dynamic like something like skyrim, but they are great smoke and mirrors, that's probably where they spended most of the budget.
Gameplay wise something like horizon had waaaaay more new things going on.
Tech wise maybe, fidelity wise it has been surpassed for a while and it is gonna happen to gta6 aswell in the next gen, fidelity wise it lose right now against the best character rendering and location rendering unless you people expect wukong\hb2\shadows level of fidelity in a huge open world, it's not gonna happen.
It is gonna look bonkers for the sum of its parts, not because it look more detailed than every other game.
If devs don't get lazy i expect any decent ue5.6 or whatever version in the future to smash gta6 fidelity wise.
Tech wise, you are probably gonna need rdr3 to surpass it.