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Personally, unless the achievements are used for clever hints on finding new endings or hidden stuff in the game, I've usually ignored them in metroidvania titles.  Both those objectives can be better accomplished through player hinting/teaching in character in my opinion.

Whether the achievements badge exists or not, players can always make up their own for replaying the game later.  The key is to make the world/game/level layouts fun enough to draw them in, and give options for how they can proceed through the game.  Players who love the game can then naturally make their own speedrun/no hit challenges out of game. :)

So, the way I would be doing most achievements is:

Require the player to actually do something and not just progress through the game.

Try to make the objectives more obscure/weird/unexpected/challenge based and mostly have nothing to do with the main story of the game.

So what I'm saying is that achievements would be a "side-thing" so to say.

But yes, I agree with pretty much everything you said.

In any case, looks like achievements are probably going to stay based on feedback. :)