You are, of course, making some good points, but the best rushers in Heroes (i.e., during the first 2-3 weeks of the game) are Deleb for Inferno, Kaspar for Necropolis, Vittorio for Haven, Sinithar for Dungeon, and Hafiz for Academy. Hafiz is effective against those who initially rely on combat units (Deleb, Kaspar, Vittorio) by recruiting their units, and his gremlins, in terms of stats during the second week, will be comparable to a monster of level 3-4. So, the Academy isn't that weak at the beginning.