This is how I see the fight going...
Round 1: feeling out process. GSP get the takedown towards the end of the round and tries to do some dmg from half-guard. (10-9 St-Pierre)
Round 2: Fitch goes in for the TD but GSP sprawls out of it and reverses to get into side-control. Fitch imnmediatly gets halfguard back, then quickly back to guard. GSP will be using mild GnP but mainly defending from surprise submission attempts thrown by Fitch. (10-9 Fitch)
Round 3: I think this round will be 1/2 semi-busy strikes and 1/2 with Fitch on his back eating a bit more dmg from GNP and having more trouble firing sub attempts. (10-9 St-Pierre)
Round 4: GSP rocks Fitch with a Kick and quickly jumps on him and gets the TKO stoppage for his first title defense.
GSP • TKO • 4th round
My guess, call it wishfull thinking if you will, but this is how I see the fight going when I think about it.