UNIT - Creature Balance + Visual Changes

Realism in a fantasy world is a rather vague concept; what is unrealistic in the real world can be justified here by magic and other elements.

I completely disagree; this approach leads to complete randomness and "whatever the author feels like."
It is necessary to define the basic laws of the world (which will mostly be the same as in our world, but with magic and similar elements) and adhere to them everywhere.