I'm not rushing at all
I've fully completed all of the areas (greenwort, arlania, velarion, swamps - without enemen, lower/upper haddar) as well as their quests, with the exception of 20% of the islands, since I plan on returning there (probably) sometime and finish up some additional quests - I'm still trying to decide whether I want to play with target + faeries+dryads ... But we'll see. I'm thinking about an undead-based paladin too... since I'll be going towards tolerance by all means.
The mage isn't that powerful actually. On impossible, the game is beatable with a mage, but he'll come to severe problems later on because you'll be low on leadership, and sometimes 2 ice snakes or whatever offensive spell you prefer + soul drain/time back (provided you have it at the start of the battle) isn't enough to alleviate the troop number difference.
I agree that the paladin is very hard to play on hard and impossible, but that's what makes the game rewarding. And I have a hunch that he's not that sucky as most people claim him to be. So far I lose few or no troops in the mines against strong and very strong opponents, depending on their troops (I love that interface plug-in)