Making every character slightly smaller for better gameplay

[Algiark]

Is it possible to make every character (the player, NPCs, enemies etc.) a little smaller in size, maybe 70-80% their original size?

 

I noticed how in many action-adventure games, the environment is always disproportionately large compared to the characters, allowing larger range of movement and make the game feel less cramped. One example of this is in Batman: Arkham games, where (assuming batman+ears is 2m tall) even the lowest ceiling can reach 5-6m tall, and the doors are 3m tall. This also makes camera work very nice, since the camera has more room to move and you don't get stuck in a weird camera angle often.

 

Of course, there will be many problem if this were to be done, like animation clipping among other things, but first I just want to know if this is even possible.