if you are already thinking larger - go larger now - you will save money on cases - I'd definitely recommend the tiptop mantis - probably best bang for buck starter case (hp/cost/quality of power/reputation of manufacturer) - or it you are building a case - the befaco excalibus power supply is very good...
this will allow you to get bigger modules - a lot of the modules you have in the current rack are very small and especially when placed next to each other will be very cramped/possibly unplayable - some of them are only just over 1cm wide and when patched may not have access to the trimmers - which can also be difficult to use/not very precise compared to full size knobs
I would choose between either midi control or a sequencer in a starter case - if you choose sequencer - you'll almost definitely want a 2 channel quantizer with the sequencer you have chosen - if you actually want to play notes
nb you'll probably also want a tuner - either on your phone or a pedal - to tune the vco
I'd also recommend more attenuators - clouds (uBurst) - really needs these - likes very small amounts of modulation
I'd also recommend more vcas - use them for modulation
probably a good idea to plan to get another modulation source asap too
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities