Problem is that you can't uninstall them due to dependencies to some core packages. Or maybe you can, but I suppose the integration is so heavy that many things wouldn't work afterwards.
...to remove their icons from the applications view.
XMPP thru empathy works fine with all features of other integrated IM's. With GTalk Voice/Video plugin you can also get XMPP voice and video call support (it uses the same protocols afterall), but that's flaky to say at least.