SuperCommando--storing of away messages on the server could get really unwieldly, imagine a max of 512 chars per away message, up to 100 away messages x how many users... that just gets unreasonable. BW I don't think would support that.
Xenon14, here's a list of your stuff and our planned BW implementation if any:
1) How about delegating different away messages to different people: already in the works for BW, on the list to be implemented very soon.
2) Better video/audio implemenation: still a ways off
3) History of msg'ing (AIM+ has that): already implemented in BW
4) Tabbing different windows: explain what you mean
5) Skins: possible, will come eventually
6) Offline Messaging: BW already has
7) Spell check: tall order for a lightweight chat client
8) IM Forwarding (no more copying/pasting): possible, good idea, will put on to-do list for BW
9) Toggling other users Idling/Away MSGs: you mean whether or not you see them?
10) Window Transparency: possible, but not a priority
11) Always on top IMs: also possible, good suggestion
12) Remote desktop control: I would be concerned of security leaks
13) Builtin FTP: very interesting idea, another one to write down, it's on the todo list
IP blocking doesn't work for people on dialups... a per-name blocking would be better methinks.
Thanks for the suggestions everyone... remember, I'm not working for AIM or adding these to AIM, I'm gathering info on how to make the better client.

Since my original message with the URL is way up at the top and probably overlooked, I'll put it here again:
http://www.bitwisechat.com. Features are being steadily pumped in and many other users' suggestions have already found their way in to our client!