Academy in the late game.

Is there a universal way to choose a magic school in the late game (so that there are no minimum summons and so on)? I used to play as Warlocks (and realized that in the late game they are simply useless against all races, as they only have Chaos or Chaos + summons – effective against Orcs and Mages), but now everything seems more interesting. Please advise...

Added after 15 minutes
And one more question: at what point (1, 2, 3, or 4 weeks) should I craft the first artifact (initiative or defense + health) to speed up the game?