In the same way I would court a wait and see approach to such hefty, but not entirely unreasonable claims, it is incredibly shortsighted to base predictions of the success of the finished product, on the performance of the beta code. It crashed, was rocky, hit detection was all over the place. But, they fixed it. Speaking of betas, where is Black Ops' beta? For a game that follows a title with *huge* balancing issues and modding/hacking concerns, can the inferior developer of the two really do what the superior couldn't without a beta?
Call of Duty 4 was great, it set the bar for future Call of Duty titles. MW2 straight up did not deliver, you know the issues, certain perk combinations and custom killstreaks on top of constant modding and hacking broke the balance over one knee, and no attempt was made to fix that. Singleplayer wasn't up to par either.
Now, Treyarch has really only made half-decent titles. Call of Duty: Big Red One. Call of Duty 3. Quantum of Solace. Spiderman: The Video Game. World at War had balancing issues as well, and the single player campaign on Veteran at the end was nigh-impossible. They neither have the history nor the pedigree.
Black Ops is a massive gamble on Activision's part, and it is a gamble. If it falls through, Call of Duty receives another less-than-spectacular entry al a MW2 and WaW, and Infinity Ward's dismantling will have been an omen. If it doesn't, then I praise their success and I will be glad to have been proven otherwise. But nobody think for a second that just because this is Call of Duty that this is a done deal.
..I'm still waiting on that beta, though.