My 2 cents
Should they have their own BOD--yes for reasons stated above.
Should they/we be separate organizations--I say no. SC has grown under uspsa more than it ever did. The added exposure in magazines, publicity, etc that comes along with the number of shooters in uspsa is invaluable, IMO. True there isn't a ton of crossover, but there is some due to that added exposure.
How much publicity would the sc nationals have had without uspsa? Not much I think.
It's relatively easy for a uspsa club to go ahead and have sc matches also. If they had to join some separate organization and deal with more fees, rules/requirements, etc. I don't think they would. I'm afraid sc would slowly die out.