I took the view of the company, and which one they'd want to get rid of. My own personal tastes (I'd off Hulk and WW, no questions) are much less interesting, imo.
Captain America draws the least sales and has marginalized marketability outside the US. I feel like DC would be loathe to break up the Big 3, despite WW being the obvious financial choice. It would be between her and Flash, I think.
Because of the franchises created around them, Supes, Bats, and Spidey are basically untouchable here imo. The rest are technically expendable, but any of them would leave a gap in both fans and sales.