"Legacy concepts"? Guess what amigo.
As someone in professional audio, I sure as hell use optical media every day of the week. Also as someone in audio, I need a rig that runs silent or close to it-the standard Mac Pros have done this for years....I've never seen a blower fan (like they're planning on using) of any size that did the job quietly and they have the "benefit" of collecting dust quicker. If Apple wants to ditch "legacy concepts" that is great, with ProTools no longer locked to OSX-audio people will drop their Mac Pros and Apple will loose customers. Also a crapload of people in pro audio are still using FireWire interfaces, and this rig has no real option for that that is reliable. As someone in audio, I have no need to waste my money on 12GB of VRAM and dual heat-producing GPUs that make my system run loud. I also sure as hell use internal mass storage first for scratch (far beyond whatever SSD they choose to throw in)as well as external backups.
Adapters will solve your core issues. External expansion solves the rest. Thunderbolt is there for a reason.
What's preventing the use of legacy Firewire hardware? A Thunderbolt to FW800 adapter is $29. We use these here on our MBPr machines and they work great; they're reliable and allow full FW800 speeds. Being prepared to shell out $2500+ on a new Mac Pro and then complaining about a $29 dongle seems completely ridiculous to me. There's some good reasons not to like the new Mac Pro, but the lack of hardware FW ports is not one of them.
This.