OP - the main body of your post should probaly be kept to your guilds admissions website page. Of course you are right, names shouldnt be offensive (sweat words, racial slurs etc etc). But everything else you are talking about is subjective and far too open for interpretation. If you and your guild dont accept or group with players who's names you find un-immersive or inappropriate then thats up to you and you guild.
I remember having a good debate with someone on the LotRO forums regarding names. He was on a RP server and said he would report someone with the name "Nightblade" citing it as in-appropriate and against the lore and borrowed from another game. When someone pointed out that Aragorn's ranger name, "Strider", was also from a computer game then he went all "The great Prof. Tolkien himself chose that name so its allowed.".... yes he also chose Ghan-Buri-Ghan and trolls called Tom, Bert and Bill. In the same respect, George Lucas has some (IMO) silly names - Naboo anyone? Ok I cant think of anymore
Yes first impressions are important but unless the name is very offensive it shouldnt be judged as anything more than "just a name". I've seen good players with bad or silly names and vice versa.