First off, congratulations! The Phoenix definitely looks promising for the mage for this low to mid level campaign.
And thanks for the intro.
Though I must say that I don't play KB as much as the other hard-core KBers since I only complete each game once.
Anyways, things I noticed for this campaign:
1) One day campaign, and doable very quickly. Trolls seem to spawn at the latter shops, so Impossilbe-(any class) could just finish the last few battles at night and still complete it in one day. Stoneskin is everywhere, and Paladin even starts off with Divine Armor.
2) If going for a high score Paladin is the go-to class. Medal (from giving 20k gold) provides +5% XP and Learning 1 provides +10% XP right off the bat. Remember, it is a lot easier to level up in this campaign, so that +XP means a lot. See base score computation below:
(100 + (100 - 1 day))*(1 + (0.02)*(total levels + 1 quest))
So a level 16 character on impossible gets 664, getting +10 to the score for each level higher.
3) Sadly, if you want to grind you still can. I've restarted a couple of games and some spawned many upgradeable items. That means more XP/gold and more chances of grabbing an Ancient Knowledge scroll from a dug up chest. Sure, money is a problem, but you are given a very easy battle at the start to try and dig up a wanderer scroll (which if it is not an AK you could just sell for a lot of gold). Note that just one AK covers more than half of your required battles (not counting item upgrades).
4) Due to the shortness of this campaign it's hard to build up the "perfect army". So you needs troops that are "just great" by themselves. Droids at the start, trolls and dragons at the end.
This is all theory though. Money is definitely a problem for a no-loss high score run to buy your army, upgradeable items, and the decision to give 20k for an extra +5% XP. I'll give this one a try sometime soon.