I was curious what sorts of settings people are using in custom skirmishes against the computer.  I found that if I adjusted the spawn rate to "high", the creep strength to "high", the tower strength to "high", and the XP rate, gold income, flag capture, and war rank speeds to "low", the game felt a lot more "epic".  I really had to work uphill to knock over the enemy citadel, instead of just getting to level 15 and then slaughtering everything in my path.  Lots of fun.