Mages are easy to level up; then they aren't so bad. Just hire 1 mage and 9 clerics and put a defend flag on the mage. He will level up when fighting something like a werewolf: the clerics will be too busy healing. I tried this once to get a high level mage to upgrade to an icemage for my house of lords. It cost a bunch, but was worth it. For rogues, you should make them your fighting class. If you just make them as a side class and buy all of them plus their upgrades you will do well. I found that in multiplayer rogues were especially useful due to the amount of time they could level up in before you swarm your opponent.