As mentioned in a recent post of mine, I'm also getting to a point where I feel I HAVE to start looking for something else... or at least keep an eye out.
I don't need as much I/O as you, but when looking at alternatives, also stumbled across the PM5D (and PM1D) before. I didn't look deep enough into it at the time, but let me say this:
I have NEVER, EVER, EVER owned/used a piece of digital equipment that is as unreliable as the D8B (or the HDR/MDR for that matter). I mean, it's their age, of course, but I have a lot of other really old gear that doesn't suffer as much as this stuff.
Besides... I hope I won't offend anyone, but when it comes to mass-produced products (vs. hand-built higher end stuff), IMO, nobody beats the Japanese when it comes to designing and building reliable products. Maybe not the most inspiring and exciting products, but from my experience, that stuff just works.
I never worked with the higher end Yamaha digital mixers, but owned a 01V right after it came out, worked on an 02R occasionally, and had a Promix 01 at work, back then. Never any issues (but the Promix 01 is weird and only runs on 48 kHz). There’s some details I didn’t like (e.g. automating the faders from a DAW, would “lock” them to the touch… you couldn’t just grab a fader and move it somewhere else, when automation was on… this annoyed me A LOT on the 01V).
The pres on those Yamaha mixers were super-bland, though. Like, if you want it to sound weak-sauce AF, use those. Otherwise, use a different pre. IMO, they’re “cleaner” than the D8B pres… but have even less life in them.
On the other hand, though… not all Japanese digital mixer designs are good. I had to use a Roland VM7100 at a different job, later on. I HATED that thing with a passion. It was crazy unintuitive, and I remember trying to route something out the S/PDIF port and giving up, after like, 30-40 minutes of looking (I guess I could have looked in the manual, but didn’t). I always hated Roland’s user workflows and menu structures, though - also on their synths - so, maybe I’m biased.
Anyway… personally, I’d also put everything on patchbays and patch in what I actually want to use on any given project. It’s actually VERY intuitive and fast to work that way, once you’re used to it (otherwise, how many 8x8 MIDI interfaces do you have stacked, to even trigger all these synths at the same time, without patching “something” (in this case, maybe via a MIDI patchbay)?
If you “insist” on having that much I/O, then personally, I think I’d get a couple of rack mixers and cascade them, then control them from an iPad or something. The PreSonus Rack mixers work that way.
If budget is not an issue… I mean, the higher-end digital mixers, usually have separate “control surface” components, and separate I/O and processing components. With those, you can usually customize how much I/O you need, and then you control everything from a “generic” console that works for this type of mixer system… regardless off how much I/O you have connected, etc. This is not a market I can afford to look in, though… so I couldn’t even give you examples of desks that do that… but you probably know what I’m talking about anyway… but it’s out of most people’s budget’s reach
I’m not sure what I’ll do, still, when I get rid of the D8B… maybe a stronger focus on control surfaces and ITB mixing, and more DSP to support it (e.g. the UA Apollo I have and the Satellite unit with more DSP that I have, do pack a punch, and go pretty far)… but I’d still keep a small mixer for real-time monitoring (e.g. DSP processed stuff coming out of the UA interface).
Sorry… I don’t really have any useful feedback… but as much as I like the D8B when it works, IMO, it can’t get much worse than that, when it comes to reliability, etc. (After I switched the rack unit the other day, it worked for 2 days, and now I had to start 3 times again for the past 2 days, b/c of meters being stuck again, and once a fader motor was stuck on the bottom… calibrated and fixed).
I think I’ll start counting the days on which I do NOT have to troubleshoot the D8B when trying to turn it on… would probably be a lower number than the other way around…