William Weld himself should have run against Kennedy. He would have won for sure.
He was too egomaniacal with wanting to win a 2nd term to try to take on Teddy. Witness, however, after he had that under his belt and reverted to his usual "bored" phase, wanting a quick exit from the Governorship, that he couldn't even enunciate WHY he wanted the Senate seat when he ran against Frenchie. The bloom was off the rose at that point (if it ever was in the first place).