I have found an interesting video about size changing.
It seems that if someone could shrink to tiny sizes (such as Ant-Man or the Wasp) he would lose all his body heat and die, and if he grows to giant size (Giant-Man, Stature, Atlas) it would explode and leave the insides all over the room.
So, let's everybody get a superhero, get rid of all those convenient plot devices such as "a mutant is immune to his own powers", and imagine for a moment if he really had that fancy superpower in the real world. How would each one be screwed?
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Note: This is just a game, of course. None of this would apply for earth-616 or most others, and they are still alive and well in those universes.