The only problem with the Core chips would be the lack of PCIe lanes. 16 lanes is just enough for a GPU and two NVMe drives, really. Unless you’re ok with 1x or 2x.Both systems offer poor value at the lower spec though because they are Xeon based and everything is more expensive. You'd be better of with a higher end i7/i9 system in that range.
The Xeon chips make much more sense in the higher configurations though where you can get crazy core counts, although the clock speeds on the mac pro takes a nosedive, which I don't know how that will work for pro audio.
I still think the imac pro might end up outperforming the base level mac pro here for less money and with a screen attached. In the higher configurations the mac pro will come into its own but the price at that point will only really be an option for bigger businesses who have the money to fill it full of GPU's.
I still think there's a big gap in Apple's line-up here, people who want power and expansion possibilities in a desktop format but aren't going to drop 6-10k or more on a computer.
From what I've seen most of this market has switched to a PC, are they going to return to Apple for an 8-core, 32Gb RAM, 256GB of storage machine that costs 6 grand?