Noone has said that? It's the regular camber that provides more grip and stability, because it 'bites' into the snow better than RC.
If you take two boards that are exactly the same but one has rocker and one has camber, then yes. The cambered one, even in a single size down, will have more edge hold. When you go from a 159 to a 153, even with camber you will get LESS edge hold. The board is not designed to manage your weight. You WILL out torsion the tips and you WILL wash out.
Wanting to go smaller is entirely different. I would like some more manoeuvrability; and friends of mine on small boards say I'll have a lot of fun being able to whip it round more easily.
If you want more maneuverability than your soft, appropriately sized, center rocker park board, ride better. At the very most drop down one size and get something stiffer. Center rocker is already the most maneuverable camber style out there. If you take my advice and only drop down to that 155-156 size range and get camber, it will still be a little slower to move around compared to your Color.
I've got a stiff 161cm cambered as well and combining my experience so far; the things I enjoy doing and talking to a number of different people, I think there's a nice space in my quiver for a small cambered board.
That's fine. I really think you would have a lot more fun on a Live Reverse 156 or a 2013 YES Greats 156, but if you just have your head decided on the Live Camber, just don't get the 153. Even as stiffer board it will not ride as designed under your weight.