How about having an option for automatical leveling before starting the game? I mean you get a premade build and would be applied by itself. That would be awesome for n00bs to get the game learned, plus would help casuals to get in more often because they don't have to remember the skill build.
Veterans would get their own builds, of course, more oriented to what's really happening in the battlefield and what would be needed.
IE:
Support Erebus -> Fog oriented
DPS OAK -> Spirits + selfbuffs
Mage rook -> Stone + mace
Tank/support Rook -> Archers + towers