SF or The City please -- never call it "San Fran"
I vote for bringing back Frisco. It's a lot easier to say and write.
Complaining about San Fran as a nickname is...odd or idiotic/strange (why the objection?). It's unique, everyone knows what you're referring to, it's not derogatory - merely a truncation, why the objection?
Chicago's nick as the 2nd City is a reference to the rebuilding after the great Chicago Fire of 1871 (and the source of the MLS team of the same name - and a source of pride).
Now, our nicknames for Columbus, OH are intended to be derogatory (Detroit south). But, I don't get the objection to San Fran...