Agreed.

I made a fullstack of generals only and they got defeated by 2 demicannons and 1 milita. Lost all of them and inflicted 9 casualties.
Played it myself, I lost just about 12 men and not a single unit.

What I think is that:
a. Artillery count for a lot in autoresolve, especially if you have at least 1 infantry in the stack as well
b. Light infantry counts for just about nothing
c. Cavalry don't count for much
d. Galleys/Light galleys cannot beat anything - I sent 1 sloop to attack 9 light galleys. Sloop won in autoresolve. In manual battle, the galleys tore the sloop apart.

Also, when you win an autoresolve agaisnt the AI in a field battle, both sides usually take equal casualties even if your army clearly outmatches them. If you lose a field battle agaisnt the AI in autoresolve, you always lose more than 70% of your force. Very fun indeed. Can't even autoresolve against an enemy 2 unit raiding stack anymore without taking more casualties and possible losing the battle or the AI surviving miraculously (because autoresolve favors it and lets it keep 50% of its force) and getting transported for free even deeper into my territory.

Note I usually play VH/M, so battles (autoresolved) are considered M, not VH.