Dragons:
Blacks .. eh they're ok but their magic resistance hurts more than it helps imo. Give me a slightly weaker version that I can stoneskin/heal any day (see below..)
Greens. they're ok. Survivable enough with stoneskin/heal and the mana is nice but a little low on the damage.
Blues.. haven't tried 'em yet.
Reds .. are where it's at .. at least in previous games. I did quite a lot of impossible no-loss mage in AP with a single stack of red dragons.
Chuck a stoneskin on them, greasy mist a bunch of enemies and fly in and destroy .. works particularly well with fire-rains mixed in
Seriously with high-crit, two-hex hit and greasy mist their damage output over 2-3 rounds can be just insane! At the end of a couple of rounds when your health has been whittled down .. 1 mana heal back to full health.
Sure you can't rez them but, with proper planning (particularly as a mage) you will never need to.