I want a freakin' medal for pouring through this thread... but a few observations...
...I'd be sad for the demise of Magsafe, which has saved my expensive investments MANY times...
But I am running an Mid-2010 Mac Pro purchased in November 2011 - which shows even then Apple's sluggish attention to the line. I am a Graphic and Web Designer and don't need the absolute highest performance. The Machine is well pampered and in fine condition, runs well for six years old, tho I do see some sluggish moments - mostly to do with HD access. (And why in steaming hell is MS Word slower and slower to launch than Adobe InDesign? ... I digress... ) But many of the enthusiastically touted "magical" features of the last several OS updates are not supported on my machine. But other than the base hardware ( and price ) the New Mac Pro is now apple's least advanced machine. I was recently in an Apple Store, and the one Pro on display had almost no non-apple pro-class software on it. No Adobe Creative apps, no Pro Tools, no Autodesk, no Maya... Shows a lot of interest in this market segment, no matter what you might consider a "Pro" user.
But I still love the beast, as it's a BEAST, and I can tear it down damn near to the motherboard, and pack it with all the RAM, storage and PCI Cards I can afford, a full suite of connectors. When the thing finally has a fatal fail - will most likely "cross-grade" to a tricked out iMac to get a large display and more up-to-date tech... and save a little scratch. Reminder Apple quit their Apple Display, no successor even rumored.
...
But Apple hasn't even TALKED about the Mac Pro since they introduced it 2013. That's not sekret planz or even benign neglect, that's actual disinterest. Not a priority, folks. We're not a big enough market to devote a lot of attention too. Most of us they point us at iMacs or MBPs, or even the iPad Pro – which I do admit is some freakin' spiffy kit. The tiny sliver of pros that need the absolute top performance and configurability are defecting to Windows for available workstation class machines.
...
The iMac and Mac Mini MAY get updated, even upgraded - expect good, but not top-end processors, or graphics chipsets. The trend towards more consolidation will likely continue - decent chance for Thunderbolt with USB C, and lightning.
Mac Pro? Longshot outside chance of a processor update. I wouldn't bet the &%$#ing rent money that it even gets mentioned.