Actually, I realised that it's not so much because they are white, as that their outlines are faint. Anyway, it's a complete rabbit warren once you start looking for icons on the Web: license agreements, different sizes and formats, etc. I see that there are lots of emoticons available for Xenforo (see here:
http://xenforo.com/community/resources/xenforo-extended-smilies.906/), some of which may have been available when you first started the new forum. They look OK to me, certainly better than the ones we have now. I think one or two people might have reacted to them because they weren't like on the old forum, but in time we may have got used to them.