I won't give you a specific suggestion, but rather an analysis of your current setup.
- The blade: flexy, controllable, can kill speed well and as such is suited for a defensive style.
- Rakza 7 Soft: I found too soft rubbers unpredictable in the past (combined with a flexy blade, I played an Appelgren Allplay). Control in defense (for me) revolves all around having your setup react *exactly* how you expect it to. The flex of the blade, combined with soft rubbers, can lead to a very small line in which a rubber's catapult gets activated or not (so you go from overshooting to dropping the ball in the net).
Also, soft-on-flex then reacts relatively OK up to the point where you start hitting so hard the flex "kicks in". With a soft rubber, this can lead to the rubber bottoming out and the ball basically getting a wood kick -> again, ball goes in a different direction.
If you want to keep with a relatively flexy blade, go for at least a medium hardness, and a linear, non-tensor non-fancy-catapulty rubber. For more speed-killing, take a thinner sponge. More allround play, take a thicker sponge.
Pretty much any rubber will do here, just don't make it too soft.