Yes. Lots.

There are no filters. You have only one envelope generator. There are no VCAs. There are no LFOs or utilities. How do you intend on mixing your two different wavetable modules?

The Metropolis can output quantized scales and MIDI from an external source will also be quantized, so why the big Instruo? I don't have a problem with the RainMaker, but it's basically the only thing that'd you find accessible plugging in an external sound source.

Don't take it the wrong way. But I think you've put together a rack without the knowledge of how modular synthesis works. If you were to buy all of these modules, you will spend a lot of money and not get very much use out of it. At this point, you'd be better off buying a copy of Serum and staying inside of the DAW.