Just to expand on the previous point (an interesting, yet obviously flawed point, which seems to have been sent to node heaven): His point being (summary) God=Christ, Christ=Jesus, Christianity worships christ therefore Jesus returning as Christian= Self worship = Satanic.
is based on the teachings of Jesus
. Whatever else you think about him, his actual existence is hard to question as multiple religions recognise him in one form or another
As such Christianity is centred around worshipping God in the way Jesus taught not, as such, worshipping Jesus the man. Jesus was simply an embodiment of God on Earth. In other words Christianity is praising God in the way, taught to us by Christ. So if he came back he/she could come back in any form under any religious denomination God chooses - including Christianity.
I think a much better question is, if Jesus returned, what would happen and why would he come back?
Would it be the apocalypse, or to re-new faith in the church he began or would it to bring a newer version of faith to the world. After all Jesus was a Jew and Christianity is a modification on those teaching, combined with the life and times of Jesus Christ.