I've spent probably a month total in DC, so I don't fully know its charms. And it's certainly a city that I get the appeal of, and I wouldn't be opposed to moving there if circumstances brought me there. But some thoughts:
Walkability: for pros, DC is flatter and cleaner. The Metro is cleaner and more reliable than Muni. For cons, the city itself is a bit more spread out, and its hinterlands (e.g. Tysons or Silver Spring), although accessible via public transit, are much less walkable than San Francisco's hinterlands (e.g. Berkeley or Palo Alto). But the biggest issue is that D.C. is just not really walkable in either the depths of winter or the heights of summer (although evenings can be pretty pleasant, and you can actually enjoy an evening out on a patio). Maybe I'm a wimp with low tolerances, but that's six months of the year gone right there.
Diversity: SF is around 1/3 foreign born, while DC is like 1/6 or 1/8. Almost half of SF speaks a language other than English at home, while DC is more like a quarter. DC is diverse, just not as diverse as SF.
On the diversity angle, foreign-born is not the only metric. DC proper is about 45% Black which is an important part of its history and identity as a city. DC almost never gets snow so the "depths of winter" is a relative term. I walked and biked 365 days a year and so did most of my co-workers. It was common to not own a car, especially for younger people. In the hotter summer months I adapted by wearing lighter clothes or shoes for my commute and changing at work. I also kept a change of clothes at work in the event of a downpour, which was rare anyway. Everyone else deals with the same thing, so it's not weird to pop into the bathroom to change from shorts to pants on a hot day. Outdoor dining does shut down for a few of the colder months, but then when the first tables go outside again it can be a thrill. I get that the bay area weather is practically perfect every day; maybe I just don't require perfection.
Metro absolutely does not serve many areas. It's a far cry from NYC or European cities, but was totally workable as long as you stuck to the city and certain suburbs.
Walkability: for pros, DC is flatter and cleaner. The Metro is cleaner and more reliable than Muni. For cons, the city itself is a bit more spread out, and its hinterlands (e.g. Tysons or Silver Spring), although accessible via public transit, are much less walkable than San Francisco's hinterlands (e.g. Berkeley or Palo Alto). But the biggest issue is that D.C. is just not really walkable in either the depths of winter or the heights of summer (although evenings can be pretty pleasant, and you can actually enjoy an evening out on a patio). Maybe I'm a wimp with low tolerances, but that's six months of the year gone right there.
Diversity: SF is around 1/3 foreign born, while DC is like 1/6 or 1/8. Almost half of SF speaks a language other than English at home, while DC is more like a quarter. DC is diverse, just not as diverse as SF.
I agree with the rest of what you said.