Vilk, I am all too comfortable with the buffs and durations and such as well, but the mage has substantially less troops than the warrior, and on impossible, the buffs + the troops do not always suffice. Even with a good tank+target+stoneskin+magic shield, you need a lot of backup power to beat the enemy army (especially the hard battles vs. heroes and the bosses).
If I am to play with buffs, I would rather do it with a warrior (although I used the same strat with the imposible paladin in the 11 day victory) and go with magic shield + target on the tank on the first round. Depending on the enemy army, the warrior can easily afford glot's armor or soul drain. The tank will take quite a beating, but the ranged troops will get a shot in. Then it depends. If the tanks have lost way too many units (I would take that into account when I see what I'm up against and will not use soul drain but glot's armor) I would use time back + target at the end of the 2nd round (since I didn't cast any spell on the 2nd round) and still have full complement of tanking units, while the enemies' numbers have been reduced.
Generally, there is no need to use a char for something he's not good at - like a mage for buffs + army style of combat - because even if you get leadership upgrades starting from lvl 2, you will end up with up to 23k leadership, while a paladin can go over 28k and a warrior with proper items can go way over 30k (you can view the high scores thread for more info about final leadership values -
http://forum.1cpublishing.eu/showthr...ght=high+score), which makes a world of difference. In addition to that, the mage has generally lower atk/def attributes, especially if you go for leadership items and not defensive items. For example, a mage with mostly leadership items will barely make 20, in atk or def, while a warrior will have over 30 def and over 35 atk.
I'm not saying it's impossible to play the mage like that, of course
It's just a bit odd to use a char for something he's not good at.