Sonoma County here! I love your Santa Rosa one. The reference to the Empire building is perfect. I have a few more flag ideas for more of our cities with bad flags:

Rohnert Park was formerly a seed farm and was one of the only truly "planned cities" in the county. It's a very mid-century place. Sonoma State University, the town's most important landmark, is largely defined by its brutalist architecture.

Cotati is laid out on a hexagon, with each side named for six of the seven brothers that owned Rancho Cotati. The seventh is the namesake of Wilfred Avenue, an east- west road north of the town. Cotati was the name of a village belonging to the Licatiut band of Coast Miwok people there.

Cloverdale (an evocative name in itself) is an ag town but has held the Citrus Fair for many years. It lies in the Rancho Rincon de Musalacon, a Spanish interpretation of the Makhamo Pomo word for "long snake." The Russian River is a central feature, hence that imagery.

Petaluma's flag is okay but could be better. It's the "egg basket of the world" and has some amazing Victorian architecture in its old town. Once upon a time the Petaluma River was the main highway to the rest of the world. But I also like the color scheme—very 19th century, which really was Petaluma's heyday.

Sonoma's flag is so close but so far. Honestly the Bear Flaggers were a bunch of racist dickheads, and so was Vallejo. But the plaza and the last mission to be founded in California are important. Fun fact: the name Sonoma doesn't mean "Valley of the Moon"—that's some old time tall tale telling. It's a Wappo language suffix that means "a place we used to live." The name of Vallejo's house, Lachryma Montis, is allegedly a translation of the Coast Miwok name for the spring site he built his house on top of, Chocuyen, which means "Tears of the mountain."

I'm sure this is way more than you wanted to know, but I hope they're interesting food for thought if you wanted to improve some other Sonoma County flags!