Hey there, thanks for the detailed images!
The way I've built a mage is to always focus on Distortion 3, Summoning 3, Chaos 3 and Higher Magic in that order. For artifacts, I focus on Int, mana, and mana regen stuff. For my dragon, I focus on getting Mana Accel up to make up for my loss of Concentration (I left it at the 2nd highest level, which nets me 19 mana for 16 rage as I find that much better than 25 for 25.) Since Demon Portal 3 costs 35 mana a pop, the couple of points a round that Concentration gets me is peanuts (I eventually get this skill but not till after I've gotten all the spell upgrade ones and Higher Magic first.)
Distortion is the single strongest school by far. My Level 3 trap does up to 5500 damage and poisons while my Level 3 Fireball (regret getting this) only does 2900. With Stone Skin Level 3 and Mana Spring Level 3 (+15 defense!), my Demons/Executioners that I summon can defeat stacks that are 3-4 times stronger than it even though my mage's attack/defense are a crappy 5/1.
My personal opinion is that I find Glory to be a complete waste of runes. Due to my playstyle, I rarely use full leadership to begin with (I'm running around with 1 troll when I have over 8k leadership.) The Attack point in Might is a waste too. 1 extra attack is not worth the 4 red runes you need to spend for a mage due to how few of those you get to begin with. Instead, they are put to better use on Dragon Training and more importantly, Anger (this is important to get rage for Mana Accel.) Holy Anger is also a waste of runes in the beginning (though this is a great skill for later) mostly due to how infrequent Demon/Undead encounters are then. I usually go after Learning 3 as soon as possible with my green runes instead (+xp should be get early or not at all really.) Since they give Intellect, I will get this eventually but the nature of learning is that you benefit from it more if you get it early. Neatness is invaluable to a mage (Level 1 will suffice for a while) due to the crystals you'll need to upgrade your spells. Plus Absolute Balance is the easiest way for a mage to gain rage.
For spells, Berserker is amazing at Level 3 on demon portaled units. You're gonna have them attack AND die anyways, why not add a crapload of damage in the meantime?
On my 35 Int, Berserker 3 adds +144% (so the unit does two and a half times normal damage) for FIVE rounds and it only costs 8 mana.
As for your army, I do wonder what the paladin is doing as he seems to be the odd man out. Here's why:
1) You don't have Phantom and your Distortion is at Level 1.
2) The only units he can resurrect are your Archmage and Inquisitors.
3) Your dragon is pretty mobile and I imagine your main tank. That means your slow paladins probably don't see a lot of action.
Your effectiveness would go way up if you replace the paladins with a shooting stack (Evil/Normal Beholders if you can get them due to their sleep attack or Demonologists if you're that lucky.)