I say keep it an all westcoast album and feature up and comers and/or emcee's who need their dues with a few verses/hooks from others ofcourse.
Have Bishop Lamont featured heavily like Snoop was on Chronic or Hittman on 2001. Have The Game on a couple songs, get Crooked I to drop a verse, have an all DPG song with Snoop, Daz, Kurupt, Lady of Rage & RBX. Get Knoc'turn'al on a verse and a hook or two, get Xzibit & Eminem back on a song together with himself. Maybe even Mitchy Slick, Tash from Tha Liks, Ras Kass on a couple.
If G-Unit is to be featured keep them minimal, a few 50 Cents hooks here & there and perhaps one verse, a song with Stat Quo, Young Buck & Devin Tha Dude. And a song with Nas, Eminem & Jay-Z too.
peace.