Aid Another has one design weakness. It's a standard action. If it were a Swift Action, it would be used a lot and it would be balanced (one ally against one enemy and a roll that may or may not work at low level).
IGG is not balanced. You just like it because it is your PC. I bet your DM is not as thrilled with it as you are because he understands the imbalance of it.
Are you claiming that it is balanced when compared to other multi-target abilities like Inspire Courage or Bless or many many other abilities that can be countered, are rounds or minutes per level instead of 24/7, and do not modify the dice by 4?
No save.
No significant counter.
No failure chance.
No limited duration.
A huge penalty.
I'm surprised your DM didn't ban it outright.
It's not just good. When compared to other game abilities, it's outright broken and there is a valid reason why your DM bitches about it.
It's Persistent Mass Mage Armor that auto-stacks with other armor for up to 8 allies around you. Persistent (+4 levels) Mass (+4 levels) Mage Armor that does NOT stack with armor would be a 9th level spell. We'll call the fact that your allies have to stand next to you (con) a wash with the fact that it stacks with any armor (pro).
So you think that a 9th level spell equivalent is balanced for your PC???
That's the problem with many of the newer abilities in the newer books. Someone at WotC who really understands game balance is not nixing them and these attrocities are showing up in people's games.
Sorry, but IGG is just plain beyond broken balance-wise, regardless of the fact that you like it for your PC.
If I were playing your PC, I would talk to the DM and say "You know what? I now realize how broken this is. I'd like to replace it with a stance that's not quite so uber, is that ok with you?".