I’m not clear on what you’re really trying to accomplish, so perhaps you aren’t clear, yet, either? You seem to be flailing around.
Your first complaint was that your SS sounded “flat”. That is the sort of thing one usually addresses with effects and other tools to affect the stereo field. QPAS and Mimeophon would be good examples, staying within the Make Noise stable. You might be well served picking up a good reverb pedal (Space, Empress, Big Sky, BAM etc.) to add lushness to your palette without monopolizing the Erbe-verb. If you’re stubborn about keeping everything “in the rack”, then you could look into the Happy Nerding FX AID or TipTop ZVERB.
X-PAN is a good module, useful for CV-controlled panning, crossfading between multiple sources, some audio-rate modulations, and it’s a nice sub-mixer. But you then wander into a various ostensible shortcomings of X-PAN and inquire about stereo mixers (I have an exhaustive roundup of those) suggesting you now want an end-of-chain mixer that everything converges on. There’s certainly nothing wrong with a stereo mixer, although I’ll point out that approach is not itself exemplary of “the MN usability and philosophy”. Later, you seem to talk about wanting your skiff to be a standalone instrument, but I’m not sure.
Here’s my suggestion: put down Modular Grid and stop trying to master plan. If you’re interested in, say, QPAS, there’s absolutely nothing wrong with picking up a skiff and extending your Shared System with a module or two. Keep it about exploration, evolution and inspiration. If you find yourself short on modulation, pick up another Maths (if you like it and prize familiarity) or try some other modulation source that intrigues you—no need to make a choice preemptively.
