Todd Roybark
Hero
What is appropriate for one edition isn't necessarily appropriate for another.
There are sign posts to guide us within 5e, that are 5e coherent, and consistent with history.
Primal Champion can give a Barbarian 24 Strength and Constitution.
A caster of Wish, ‘unshackling’ a single ability score at 17th level, seems to be a much weaker alternative, 3 levels earlier.
A 22 ability score, (in the spellcasting ability score for a caster,) is not going to destroy a game.
Likewise a +1 to an ability score is worth exactly half an ASI. Seems fair, for a rare but risky application of Wish.
All of this assumes restraint on the part of the player. Having an Ace up your sleeve works much better, when people aren’t looking to see if you are cheating.
As for the mountain, I never thought to drop one on someone. As a player it would be cool, to know that I summoned that. That I as a player, got an opportunity to change the topography of that shared intersubjective creative space that is the D&D play experience.
It doesn’t matter how many times the Paladin, Divine Smites Critical Hits for 96 damage.
The Sorcerer can always point to the mountain in the distance, and say “I made that”.