There was a suggestion to make mages with a guild a dead-end branch, meaning that after golems, you could immediately start building djinn and nagas. Then you could invest levels 5-6-7 in the Castle on level 1.
And group djinn would provide a +1 speed bonus in confrontations.
Regarding heroes, there were plans for a significant buff to the Scholar, so it's not certain that replacing him with another skill would strengthen the hero.
The idea about Halon didn't occur to me. It's interesting, I need to think about it. However, it might be better to choose a less effective wizard, for example, someone specializing in obscure spells. Mysticism is still a relevant theme.