I think Erica makes a dedicated drum sub-mixer, and the Moffenzeef Moffenmix is really fun if you can find one secondhand. I always recommend the Happy Nerding 3xMIA for a mega-useful mixing utility. Happy Nerding also makes the 6Mix in 6hp. I've found sub-mixers to be an integral part of my performance oriented patching. The G-Storm Electro Infusor-X may be a sub-mixer worth looking at too.
I've also found Quadrax to be a quick and smaller alternative to Maths (though it's missing Maths' handy attenuverters. The 3xMIA can make up for those).
I can see getting rid of Marbles, but I would reconsider getting rid of Plaits. While it may not be the coolest oscillator in the world, it is one of the most versatile and sits nicely in a mix. I can always find a way to put Plaits to use in almost any patch.
Have fun and good luck!