That's just the way it works at least in regards to android phones and Verizon. All 3 I've had (OG Droid, Fascinate and now the Thunderbolt) do it the same way. Not sure what you're looking for as it still works. Setting no answer forwarding to your google voice number works to get voicemails and #2 is correct as it actually dials a google trunk number which changes periodically and is what appears on your bill.
Perhaps I haven't explained the situation properly. I agree, number one isn't an issue, as there is a solid workaround, even though it doesn't properaly allow users to set up voicemail. For number 2, it is a real problem that is NOT evident in any of the other Android devices I have tried. I have tried Google Voice integration with the OG Droid, Facsinate, Inspire, Droid 2, Atrix and the Thunderblot. The Thunderbolt is the only one that exhibits this issue. Usually when you dial a number on Android, it will bring up the little bubble window on top with the Google Trunk number and then show the number or contact you were calling once the bubble disappears. The Thunderbolt, while it brings up the bubble window with the Trunk number, it still shows the Trunk number after the bubble disappears in the dialer. This does NOT occur in any of the other devices I have tested. It is a bug.
In the Google Voice app, go to Settings. There is an option for how outgoing calls are handled....
1) Use Provider for all
2) Use Google Voice for all
3) Use Google Voice for international only
I know that's know the wording, but those are the option types.
When you installed the Google Voice app, it asked that up front, but the default is to use the Google Voice for calls.