Easily one of the top cities in the world.
Slow your roll there.
Does it have nice weather? Yes.
Is it a good tourist destination? Yes.
Is it an amazing "city?" No.
San Diego has a ton of cool touristy stuff. Balboa Park, Coronado Island, Torrey Pines State Park, the beaches, etc. It also suffers from the same problems as Los Angeles in terms of being a western US car centric place. And, clearly, it's not one of the top cities in terms of restaurants, bars, culture, museums, theater, etc. You just have too many boring people who love surfing or golfing and then eating healthy.
All that said, I like San Diego. But, if I lived in California, I would prefer the Bay area or Los Angeles.
I only know San Diego as a tourist, but all my visits to San Diego have been wonderful. And I don't understand how you can say that it's not a top city in terms of museums when you have Balboa Park right in the middle of the city.