Perversely, the lack of gold in Dom2 has a tendency to increase the mage/troop ratio. In Dom1, there was often enough gold that the limiting factor was castles/labs. One recruited as many mages as one had sites from which to do so, and used the leftover for troops. There tended to be discussions in those days about which troops were more cost effective vs which others, whereas now discussions revolve mostly around the employment of magic.
If what's wanted is "at least as many units [dying] from weapons as from battle magic", there are a number of ways to go about it, but a counter-intuitive solution that might work is to increase the amount of gold available, to the point where a player might as well recruit troops along with his mages. (Then of course, that idea might be as crazy as it appears on the surface
Another factor which tends to make mages perhaps too cost effective is that they are very hard to target. One can try flanking cavalry or groups of flyers with "attack rearmost", but in my experience that never results in said troops attacking the enemy mages - they'd prefer to move across the map to attack a single limping militia, rather than target the mages using (insert battlefield spell here) to kill them in droves. I'd actually advocate the return of the attack/fire mages order in Dom3, although I understand that that doesn't help anybody now.
Re: Recruitable Mage Rebalance - seeking comments
Hybrid Mode
