Mac Pro 2013 thoughts for audio:
– It will be whisper quiet. That’s GOOD!
– (4) Ram slot “limitation.” Unless you bought the high-end 8-12 core model in the past, you only had four RAM slots anyway (as with the popular 2012 6 core machine). Right now I have 24GB RAM in my 6-core machine (4 slots). Total overkill… (I don’t use big orchestral VI, however)
– Lack of internal drive bays: I suspect adding bays may have interfered with the “aesthetic”. Would have been nice to have that option [drive bays], but not at the cost of interfering with the cooling design. Hopefully, external Thunderbolt drive enclosures will start appearing in more abundance…
– Single processor? With up to 12 cores available, this should be a non-issue for 99.9%.
The big elephant in the room is not Apple’s redesign, but that it’s success hinges on whether or not Thunderbolt 2 peripherals make a big presence in 2014. If you have a big investment in Firewire & PCI “legacy” gear, I’d grab a 2012 Mac Pro now. Those TB peripherals and adaptors are going to add a significant cost upgrade to the already premium price tag of a 2013 Mac Pro.