I don't really like the idea of not having any say in or control over how your own corportations function in your own empire, but oh well
I've had the realistic corportations feature push a corp out of a city completely at random, which caused it to starve down several sizes and I was helpless to do anything about it. Normally I'd just avoid putting conflicting corporations in a city if I needed it that way, but with RC I don't have any say in the matter. I quickly lost interest it and never touched it again.
Unless I'm misunderstanding something here - I'd really prefer to be able to maintain control over spread when possible (Even if said control was just locked to a specific Civic or something)