Perhaps if you talk to a mod the can tell you what is an isn't acceptable?
It is extremely strict. Name changes were forbidden due to the reason of "you have to keep your reputation," but it really is a deadset "no" to anything that is not a clan tag or a typo.
I wanted to name change one of my characters from
Akilina to
Tears_of_Akilina to fall in line with the rest of my characters. This both keeps the reputation of the original character due to keeping Akilina, and adds the reputation of Me due to the "Tears" signature that most people know me by on NA with my other characters or on the forums. However, this too was denied after talking about it in irc.
Basically, nothing is acceptable if it is not a typo or a clan tag addition/removal. It is nice though that it tells you this upfront in the rules, so at least you know what to expect, which is nice and fair.