[WSzaboPeter]

I think that banning Arcane Nexus is a good idea, since the benefit is clear and relative easy to achieve it and has no real downside (other then a lot of people will hate you).
In the other hand banning Utterdark or other globals, heavy bless and other things will lead to the simple fact that nations with better troops will win. Let's imagine the extreme, that we manage to ban every "cheesy" mean to win... So someone with Arcoscephale and a bargain pretender focused on armored elephants starts near T'ien Ch'i Spring and Atumn. By the time he will research with very hard or hard conjuration or other magic to deal with the Elephants he will be raw meat. But then let's ban armored elephants too? I hope you get my point where does this goes.