Really, the treebar needs it's own set of commands, and I'm going to go out on a limb and guess that Khaled is already working on implementing some. Colors probably aren't a priority, but I doubt they will be overlooked. More important right now, however, is functionality.
For example: grouping. There is currently only one method of grouping: Network>Group>Window. Ideally, one could group certain items irrespective of their network (DCCs and Custom Windows for example), and perhaps even manually. Also, a sort alias could be added so that the user could toggle between normal (by order of opening I assume) and alphabetical sort, as well as an alphabetical sort which ignores window prefixes like "#" and "Chat". In addition, and most simply of all, an expand/collapse alias could be added so that a user could sort and arrange his/her treebar.
A personal nuisance would be solved if an option were added to stop a treebar item from expanding simply because a new window (perhaps even distinguishable by type) has been added. Everytime my "scripted instance" of a network (which I keep collapsed) sends off a rules file, it expands automatically. So, while I can get the switchbar items to stay hidden via ALT+LCLICK--it seems there is still no show/hide/collapse alias for this either--I cannot seem to keep treebar items collapsed.
On related functionality: dragging files over switchbar/treebar queries/DCCs could make for easier file sends. Not sure how realistic/possible this is, though.
As for cosmetic details, I have noticed the Top/Bottom fails to work as well (though I'm really not sure how that would display that differs much from the Switchbar). Personally, I would just remove the Top/Bottom options from the documentation, but perhaps someone else sees a good way to display it. Also, a minor detail: it would be good to have "no vsbar" and "no hsbar" options for the treebar.
Whether the above is considered or not, I'm still fairly confident that Khaled will be implementing more functionality to the treebar. This is only it's introduction.