It is not that the name "Salesforce" is bad as such, but I still prefer it would have conserved the name "Transbay" It would be like a more perdurable name, if that company gets bankrupcy, merged or change its name, so will the building, some how losing part of its identity as it happened with the Sears Tower.
I Still hate that Willis Tower name, again, not that the name itself is bad, but Sears was the identity name of that iconic tower for over thirty years, it should have never been changed, as the Chrysler building remains the Chrysler even that company left it decades ago. When you said Sears Tower, everybody knew what building you were talking about, if you say Willis Tower, it is more like, What? (you takin'bout, Willis)
Transbay would be a name like Empire State, more representative of the city, as the building itself will be a symbol of the city. And it was cool that the title of the tallest building in SF were passed from one "trans" to another, it would also be representative of GLBT community of the city.