Without an A-154 Enhanced Sequencer Controller you may want to throw in a couple of switches, the Doepfer A-150 and/or A-151, for example.
And while you're about it, slap in a Doepfer A-160 Clock Divider and an A-161 Clock Sequencer (all four modules only 16U).
Also, if you're looking for the epitome of non-randomness, a logic module (or two) like the inexpensive Doepfer A-166 or the Intellijel PLog or Spock modules, possibly also a pattern generator like the Pittsburgh Timetable or Mutable Grids 'Topographic Drum Sequencer' or just about any other Euclidean sequencer for that matter, particularly the RebelTech Stoicheia and Klasmata, and talking about sequencers, you could probably make good use of a MakeNoise Rene cartesian sequencer, and you could do with a Mutable Anushri voice module ... Er. ... and you'll probably gonna want another 9U frame. ...