I see a lot of people arguing about XP rates on upcoming TBC server.
Some people rather have it at x5 (or even higher, which would be inefficient but whatever), and some people want it at x1.
So, why not have a dynamic XP. I believe some Cataclysm or MoP server has this functionality where you can type in chat .xp 5 or .xp 1 to modify XP rates on players' side.
This would be fair for all the players even for those who want x5 for 1-58 and x1 for TBC contents because you can modify XP rates mid-way whenever you want. If you find it too challenging, you can always change back to x5.
I am not sure if TBC has the API to do so, but, would be really cool to see this happen!