Just saying they're unlikely to be going cheap on anything in the park is all. Also Cars land isn't Californian, but it fits really well within the park.
I'm with you on the wishing it retained more of its Californian charm, as it is a fantastically relaxing park, especially compared to Disneyland. But with Marvel they've got a very big brand that they want to squeeze somewhere into California (and really the US as a whole given the difficult contracts with Universal on the east coast) and sadly DCA is the only place with space. I'd have preferred a separate park for Marvel, but they only have so many parking lots that they can turn into theme parks! And I did hear a rumour that it was being considered to turn the remote parking lot into a park
I believe they'll make it all work in the end. The classic California aspect will live on in its Main Street area. The outdoor California aspect will live on with Grizzly River and Soarin'. The pier should hopefully still look good from across by Little Mermaid. Whilst Marvel land can sit on the other side of the park and do it's own thing. Coincidentally I only walked through that area once on my last trip!
If Marvel land eats up some of the crowd from Disneyland then I'm all for it!
But if I'm wrong and Marvel land encroaches on other parts of the park and gives it an overall tacky feeling, then I'll be picking up my pitch fork!
Edit: skipped Pixar land. I'll reserve judgement until I see fully what's happened to California Screamin'. An increased focus on the animation side would have been good. Yes, Senior Burrito Buzz does look fairly horrific.