Spectator mode sounds great. However I'm really mot a fan of the latest changes. It REALLY seems that the netcode, hit detection and such is completely out of whack. I've actually gone back to quake live to relive playing as though I have the 30-50 ping I actually have.
Unfortunately BF3 can never be taken seriously as a competitive game until they fix the inherent built-in lag. Run behind a wall, 2 seconds later you die. Try to snipe someone that's juking you... Good luck, just take random pop shots. Try to pull a quickie surprise jump and/or dive move... never, ever works. Playing BF3 is like wading through sour cream and until they fix that and give it as precise and quick input as CS, it's nothing but a pretty benchmark.
I really think the lag issue is being over-exaggerated. It's something I've rarely experienced in any server with a 50ms ping or lower. It's also not meant to be a twitch based shooter. A game can be competitive because of its heavy team-based nature. Being smart allows you to avoid most issues.