An Epic Pathfinder Campaign (level 60)

I'm currently playing in a level 60 Pathfinder campaign (around lvl 10 now). I'm also co-GMing the campaign to an extent.

This is a game where the main GM is very liberal and allows a homebrew of almost anything. For example, he would allow the introduction of semi-automatic weapons for a Gunslinger or he would eventually allow you to become Lord of Magic, a demigod or in my case, a Balor demon. It's a very homebrewed campaign.

What I am asking is:

Assuming a level cap of 60, what would break the game the most if you started off as a wizard? Something I should mention: he allows going on long-term quests to obtain 3.5 epic spells like soul dominion.

Wizard 20, Cleric 20, Mystic Theurge 10 and 10 something else?

Part of me wants to know so I can expect it from my players.

Thanks!

What you can expect assuming you go with the same rules from 1-20 just more of them.

full base attack classes hit everything, noone else does.
Fights take forever.
Rolling for saves rarely matters, either you can save or you cant.
No one does what you expect them to.

For example in one game, instead of fighting off the epic dragon I made to fight the PCs they just took his loot while he was attacking them then portaled away.

Rules need to be tweaked beyond level 20, alot.