In this moment(when the wind is longitudinal to the car), we can see how the RW generates much more downforce than any other part on the the top surface of the car.
It's quite remarkable how much more pressure it have there compared to the pressure on FW
and I doubt this is something particular of C32 because their FW shouldn't generate much less downforce than any other as they have few slots there.
The slots on FW might help the flow keep attached and increase L/D but the overall downforce of the "less planes" is bigger. Ross Brawn once said in 2009 that the 2 planes FW on Brawn GP generated more downforce than the 3 plane one, although the 3 plane ones have it's advantadges
More about the car, rather than go further on this more generic debate, next race will be quite blatant in showing how C32 stands on mechanical grip. From some sector times in other circuits, this year, I got an impression that the car is not as bad as C30/C31 were on this side, albeit nothing spectacular either
If Monaco confirms this, I'll wonder if any change they possibly made to improve mech grip would've damaged the aerodynamics, as a side effect.