As well as the previous problems, some people seem to prefer boards without signatures, and speaking from a personal view, after having them here, not having them here, and viewing and being a member of boards which do and don't have them, I think it's overall better without them. Yes, it's nice to read a few words of wisdom or an intelligently funny comment, but without them there are benefits too including less scrolling to read the actual posts (rather than a signature you've read a hundred times or more), and slightly quicker page loading. If you look at many boards you'll see the signatures can end up being a significant part of an overall page - repeating over and over again.
Regarding the smilies, yes, as smiles are legal (taking copyright into consideration) then more are likely to be added in the future.