It only allows computers to be named with alpha-numeric characters which don’t include space… I think they should add space.
There’s most likely a technical reason behind this restriction. I don’t think it’s too big of a deal, personally.
Correct. It would made database control slightly harder, and I believe we just don’t see a problem to it considering (if I recall), you can use underlines aka _ in it, thus alleviating most problems for splitting things apart. 
~Century0