I dont expect a new Mac Pro very soon, but it is doubtful Apple is going into hibernation for very long time right now on the Mac Pro. January/Feb would be about right in getting their i's dotted and t's crossed to release a MP upgrade.
The 5k screen in the iMac will likely have its own proprietary connection between the GPU and the screen itself to be able to handle the very high bandwidth of data needed.
It is internal connection, almost by defintion there isn't going to be some "off the shelf" cable to connect the GPU to the internal display. Most systems need custom routing due to individual variations on layout.
iFixit's teardown (
https://www.ifixit.com/Teardown/iMac+Intel+27-Inch+Retina+5K+Display+Teardown/30260 ) shows a cable with at least an additional 4 pairs of wires. The bandwidth problem is quite tractable if can just use two fully enabled DP1.2 connections. If it is internal then can combine those into one single cable since the cable is custom anyway.
At the moment, there is no simple off the shelf single cable connection (such as a thunderbolt cable for example) that can handle the same amount of data to go between a desktop box and a 5k screen.
Don't necessarily need a single cable. AMD has Eyeinfinity technology which merge multlple screens into one virtual screen.
http://www.amd.com/en-us/innovations/software-technologies/technologies-gaming/eyefinity
A similar solution ( kind of opposite direction ) is done for most current 4K display ( where the TCON can't handle the 4K so merges two display streams into one screen).
Apple probably isn't going to jump onboard with their own equipment making two connections, but Dell already has a product coming...
http://www.anandtech.com/show/8496/dell-previews-27inch-5k-ultrasharp-monitor-5120x2880
It might be restricted to GPU cards that support something like AMD EyeInfinity and/or need custom drivers but it would be a solution in the near term.
The launch of the new iMac foretells little if anything about a nMP refresh. The nMP will not be able to drive a 5K display until DP1.3 support comes with next-gen GPUs and Thunderbolt3 (which could be a couple of years away).
Again, technically no. It is likely capable. The question more so is whether the enabling drivers be added by the GPU vendor and Apple. It wouldn't be surprising to see Apple not put tons of effort into enabling the Mac Pro over the intermediate term to cover 5K displays. It isn't like the MP isn't useful unless it has a 5K display attached.
The refreshed Mini actually says more about the possibility of a nMP refresh than the new iMac. The new Mini shows that Apple has no problem updating the desktops to Haswell (even if it is long overdue),
Says dilly-poo about the Mini and Pro. The Xeon E5 v3 processors that the Mac Pro might use just relatively released. Apple couldn't have updated the Mac Pro even if they wanted to earlier in the year. So the overdue-ness factor of the Mini really doesn't amount to squat in respect to the Mac Pro. Apple should also probably upgrade the GPUs and also the Mac Pro 2013 is less than 12 months old. It is almost the exact opposite of the Mini. The MP has been recently updated so there it is not in a panic to update right now.
however, on the other hand the outcries over the deprication of the Mini in that forum show that they seriously missed the mark with the Mini's key fan base (very reminiscent of outcries here a year ago).
The outcries where the Mac Pro went on to be out of stock for months while production caught up to demand. Yeah, I'm sure the Mac Mini product manager would absolutely loathe to have that problem. *cough*. Not.
Has Apple cut off some fraction of the old Mac Mini customer base? Yep. Has Apple opened up the window to more Mac Mini customers( lower price ponts, more standard SSD solutions , etc) ? Yep. As long as the second is at least as large as the first it isn't going to hurt them. Apple lost the "2 or more" CPU package crowd. Did that hurt Mac Pro sales in 2014? There about
zero evidence of that.
It certainly won't be anything ground-breaking or "big". No one knows if or when Apple might choose to launch such a refreshed nMP...
Yearly updates only need to be better. There is zero evidence that an update would not be more performant , robust , etc. There might be a slight uptick in price but
It could happen any day between now and March or not at all.
Apple increasing 4K monitor support across a wider set of 3rd party monitors is something they can due between now and March whether they release a new machine or not. Most current 4K monitors have the same "two streams necessary for 60Hz" problem that 5K monitors also have. There should be a new wave of better 4K single stream monitors coming also.
Also if Apple has to put AMD Tonga driver support into OS X to support the new iMacs why skip the Tonga (or better) GCN1.1 options in an updated Mac Pro????? It doesn't really make any sense at all. A significant fraction of the R&D cost are already incurred by work on the rest of the product line.
The GCN 1.0 GPUs in the current Mac Pros don't support OpenCL 1.2. The Mac Pro is in part a huge bet on the utility of OpenCL. Delaying transitioning the Mac Pro to GCN 1.1 (or better) GPU blocks exactly one of the major strategic trends the Mac Pro is betting on long term.
Sure Apple is entitled to make bonehead moves.... but there is little indication they are on that path right now.