I feel you OP. It is a lot to keep track of. I'm in the process of building an optimal UI to account for all of this. One thing that has helped out quite a bit is just putting Icy Veins, Mirror Image, and Alter Time into one macro. So now you're basically cutting the spec down to keeping Frozen Orb and Frost Bomb (or w/e bomb you have) up while casting FoF / BF procs as they come.
Invocation was too much of a hassle for me as well. Rune of Power seems pretty easy to manage but I'm going to switch over to Incanter's Ward today after maintenance and give it a go. I like the passive 6% and mana regen, and the shield will hopefully come in handy during fights with lots of group/raid damage.