The problems I had with it were...I dont want to use my GV number as my primary. I dont want to change my GV number to my cell number. Each option had issues that I felt needed to be addressed. Changing my GV number to my cell made it to where txt would be comming into my phone via gv app. Yes there is a work around but ita annoying and I dont want my text stored on line. I also didnt want to change my gv number, this to me sounds like it could be a bad idea at some point in time, and cause other issues. So I set out how to get classic google voice back with the new app that will not let you just use it for vm heres how i did it, now I know this affects the Nexus S 4G with the version of GV they include...however the market version does seem to be different.
Option 1 (For Rooted Phones)
1) Use Titanium backup or some other root explorer to delete the stock voice apk, then reboot recovery and wipe dalvik
2) Once back inside the rom download voice from the market as that version doesnt seem to suffer from the shitty options that are stock on the phone
Option 2 (The proper way for rooted and non rooted phones)
1) Launch GV app on phone, and sign in, when it ask choose to change your gv number to your cell number.
2) Get annoyed and go get a shot of vodka, and wait about 15 minutes (honestly because you wont be able to change it back for at least 15 minutes.)
3) Login to gv on the web (voice.google.com)
4) once in there click the gear, and pick voice settings. Under the phone area choose to disable the sprint port number (your google voice number). It will disable and revert back to your old gv number
5) Where you mobile number is at you should see enable google voice mail for this line. Click that, and follow the instructions.
6) Click on voice mail and text uncheck email message and send sms.
7) on your phone open gv, goto more then settings make sure it says. Making calls do not use gv to make calls. make sure this phones number is your actual mobile number adjust sync options as you wish and make sure My gv number is indeed your gv number.
8) DO NOT SIGN OUT OF THE APP (Im not sure what will happen but my guess is it will break)
9) Edit your voice mail settings under call settings and change your vm settings to GV from "My Carrier" and make sure your GV number is in there.
Options: Now if you dont want to use the gv app at all you can have gv send you an sms or an email instead or manually check your voice mail by phone.