Apple should just stop pretending that it is "THE American company" when it sells/or tries to sell more machines to the rest of the world. Only the minority really cares if something is manufactured in California. Keep the build quality of the c(ylindical)MP and make it cheaper. Do it in China, in India, in Vietnam if you must. Rename and reintroduce this product and bring back the o(riginal)MP. Also, make MacMini a first citizen again. The more options the better.
1) Old/tower-style MacPro, for the "professional" youtuber, the video editor, or the poor scientist/researcher who can't afford a stack of machines running in parallel. Just reuse the old case, include the PCIe slots for GPUs but modernise it with Thunderbolt ports, USB3. Put dual V4 Xeons that can be replaced/upgraded, either by users or at Apple. 8+ slots of DDR4. The usual HD storage space for those that still prefer an internal RAID option and mechanical drives.
2) Cylindrical MacPro (rename it, MacPro Mini wouldn't sound good), for the sound engineer who wants both CPU/GPU power and silence, the DTP/GFX/Web designer who needs a multi-monitor setup without having an iMac standing on his way, the researcher who changes countries/cities every 1-2 years and wants a luggable workstation, the programmer who hates working with tiny laptop screens and keyboards. One GPU instead of two, give a build-to-order option for either AMD or NVidia. Go with i7 instead of Xeon, focus on GHz rather than cores, use ordinary RAM instead of ECC/Registered. Keep the great small case and the silent cooling solution, the Thunderbolt and USB slots (take them to latest versions).
3) MacMini for the people who want something smaller and/or cheaper but still hate being forced into an integrated screen, those who 'd like to have a more powerful and flexible HTPC than an AppleTV under their TV, those who would also want to run both Plex server and client in one device, run Roon/Squeezebox/etc services, maybe also Apache/MySQL/anything as well. Make the RAM user-upgradeable again. Besides the i5/i7s, bring a cheaper, low-end, ARM-based, fanless option as well.