Try installing "Not Call Log" from the market; it brings the phone back to the home screen after a call (or you can run some other app of your choice). This has helped immensely for me, though I agree that the dialer is sluggish and too easy to misdial from. My list of issues:
1) I wish there was a way to force the screen to lock while in a Bluetooth call, so that once a call starts I can put the phone back in my pocket.
2) The proximity sensor blanking should be optional while in a call -- incredibly annoying if I'm calling somewhere I need to listen...enter something...listen...enter something. And there should be an option to leave the number pad on the screen during the call.
3) Don't get me started on the need for Bluetooth voice dialing, which doesn't even work on the N1 -- the lack of any response to their Issue #1181 makes me think it will never be supported on the Android platform for reasons I can't understand.