Controversial I know but, whilst lots of people love maths, but is it worth 25% of your rack...?
I had a quick look as to what I'd change (for me) The preview is cached, so doesnt match what I ended up, so you may need to click through here: 
In a rack this size I'd suggest looking at the Quadrax as an alternative to maths, smaller and very flexible, can act as a vco, envelope, LFO and a "drunken walk" style variable voltage output option, and has some very clever patching / internal routing.
For glitchy fx the 2hp freez is a lot of fun, so I added that, and the FX Aid for more flexible effects (including newish drum modes, but I think you'd want to keep that separate).
I've kept the VU meter because you are clear as to why you want it... but I've swapped out the intellijel quad vca for Veils to make space for it.
I've replaced the other 2hp drum modules with the 3hp Pico drums, it comes with good drum samples and you can also load your own samples into it, it has some drawbacks (one audio out) but its compact and flexible. Then maybe consider another Pico module to even out the HP... I've gone with pico trig which can be used as a master clock, a clock divider or for drum patterns.
I've added the squawk dirty for more variety of filtering options, it also includes its own vca and I've generally found it interesting to use post stereo mix, but it gives you a lot of different flavours in a small space.
My first sound sources were plaits and twin waves... I've definitely used the twin waves a lot more than plaits... but I'm sure you have a better idea of the kind of sounds you want to play with so I've left it as Knit. For the same 6u and bassline however, I'd take a look at the godspeed, it also has a built in wavefolder.
It feels like forbidden planet could be a little redundant in this build now, but filters are great for adding character. Or swap it out for something weird or interesting: Pizza, Twin waves, Compare 2, triple sloths, tilt or ochd + links (I went with the latter)