Having trouble with Warrior on Impossible

[Zonc]

1) get the skill from mind tree that increases gold income
2) I would stick with human units since warrior has two skills that decrease leadership requirements (switch zombies to bowman)
3) in the beginning choose stats on level up instead of leadership, cause stats do not scale with level on level up where leadership does. I admit on impossible it's gonna be harsh...
4) for a warrior I would stick with order magic (dragon arrows, battle cry, bless) but it's just me (im quite surpised you managed to level 2 dist. magic so early)
5) if you can get to Hadar, go to dwarven necromancer and get some Vampires, they are excellent units
6) stick to the main quest as long as possible, exp rewards are greater and some new units appear at vendors. Islands quest isn't very challanging, you should get to the point where you have to Korodar)