Actually, when I've dealt with systems that have all sorts of different module aesthetics, I've found the various panels and layouts to be helpful...as long as they're designed to make sense. When navigating a front panel, you get used to the pattern of light/dark/color/no color that's there, and that aspect helps to make things easier to navigate...especially in low-light situations as one might encounter at a live gig. If I know that, say, my LFOs are right there between this wide black panel and that gold Ladik module, it makes it easier to simply grab the right knob after a cursory glance, whereas with everything having the same appearance, you might not be able to do that as easily.
Fact is, one thing that drove me off the hinge when dealing with Moog modulars was that constant black space, with modules denoted by the little silver strips between them (usually). They might sound awesome (and they DO) but my god, are they ever a nightmare to deal with in low light and/or when you're starting to familiarize yourself with a given system. Buchla 200 modules have much the same problem...but in their case, you're also dealing with the two different patching layers. Again, not really fun until you get past the learning curve.