Well, Symbian has been known to change UIs like one changes clothing, so you can count on it to come up with a new UI sooner or later. The current S60e5 UI is pretty decent for what it is supposed to do though (i.e. make calls, let you browser through your stuff, send and receive messages, etc.). It is indeed bland and boring, but you can hardly blame it for lack of utility.
If you are trying to access talk.maemo.org from it, the 5800 UI has nothing to do with the problems accessing that. Instead, you should blame the admin for not making pages light enough for a resource-poor mobile browsers (remember, whatever 5800 is, it is not a desktop PC with 4GB of memory and a super fast CPU). If you just mean the text input modes of 5800, its full-screen keyboard works like a charm for me, way better than prettier iPhone keyboard.