i do get the feeling that all the new stuff comes out in Euro first and only occasionally makes it to 5U - and even then, in PCB or kit form. are we likely to see the MakeNoise Rene sequencer and suchlike in 5U? probably not.
5U is the best DIY format, for sure. one major reason i picked it, years ago. but once other things encroached on my time to the point where the time vs money curve was hard to justify, and i needed a programmable synth and a good input chain for the stuff i was working on, i basically let it go for a Minimoog, nice preamps, nice compressor, etc.
another thing i wanted from modular that 5U never seemed to deliver was portability. i wanted a machine that i could sit with in the dining room, rather than having to go into the temple and worship at the altar of my huge telco rack. and i'm convinced that vertical modules cause RSI.
so now i have a few regular synths and, because i missed the mess of cables and craziness, an embryonic Euro modular, whose mission is focused-chaos, and whose size is constrained by a the wonderfully portable Tiptop Station 252. that's it, the whole thing has to fit in there. no sprawl - unless i really can't do what i need to in that size (and if that happens i should just develop some skill!).
i wish 5U was the standard that Euro is, for sure. apart from Doepfer etc, there's not much difference in the cost, IMHO, but the physical size does make a big distinction.