Here's a philosophical question for you all. You're talking about eliminating some classes from this experiment because they would be way overpowered compared to other classes. Let's assume for the moment that that is true... why should that matter? The purpose of the experiment is to build the best possible lvl5 character, right? Even if you eliminate the 3 most powerful classes, whatever was the 4th is now the 1st, and that's still going to be what people gravitate towards.
It's not like battlegrounds, where everyone ought to be able to have at least a fighting chance because they should be able to play the character they want. Here, you're making a character just for the purpose of seeing how powerful you can make a lvl5. So even if every character in the experiment ends up being, say, a druid, because for whatever reason druids are the most powerful class, then your challenge is -still- to make the most powerful character [druid] that you can in 5 levels. That's still a valuable experiment and will take a lot of thinking.
In summary, in BGs you want every class to be at least reasonably viable. In this experiment, you want to make the single most powerful character possible, which will always mean playing the most powerful class, even if you eliminate some other classes. So forget about eliminating classes and just make that one class as good as you can in 5 levels.
Besides, some people might surprise you with what they come up with to counter it. Don't rob people of that opportunity to experiment.
