Agreed, having it centrally done is better. No solution is going to be perfect for all platforms yet, I don't think.

(The on-click for iOS, while it would let you view the spoilers, would lead to unwanted spoils for some people. It's way too easy to 'click' when you were trying to put your finger down to 'scroll' - I follow a decent number of links that way and have to abort them or go back. But I think the on-click is probably still the best solution. It'd be nice if you could click again to re-hide, that way if you see the block of color turn to text you *might* be able to make it go away before you registered what it said....)