Secondary skills in Heroes 3.

I agree about the Town Portal, and that's why I mostly play 3.75.
I state this so categorically because I've tried various builds and can say with a high degree of certainty that "it works."

I haven't tried it in 3.75 yet. I'm not claiming that Eagle Eye becomes super, secondary skills continue to be divided into secondary and even less important ones, but starting with 4 players (it gets even better) it starts to bring significant benefits. That is, if you think about it, it's equivalent to getting a certain number of Pandora's Boxes with spells during the game – not bad at all. Again, it depends on the conditions, of course. If the map is, say, L, then with several players, there won't be much free stuff for each, and getting these "Pandora's Boxes" is a good thing;)
I think the idea of reworking Eagle Eye so that you get spells during the battle is a good one.