It's not a bad idea. The 2 hour time limit seems a bit long though.

I must say that adding this doesn't add diversity, or change, to the game. CW was a game changer; this is not. It' just the same thing that already exits, but it gives more rewards and you compete with more people. If they are to add something new, I expect something more surprising and which change our entire experience of the game, as CW successfully did.

But as others said, there are issues that need to be fixed first, especially GW.