Assuming there would be any support for a dead media center tech is borderline delusional.
If you are so tied in to media center, and need to upgrade, buy a small form factor pc for half the price of an Xbox .
Otherwise your 360 isn't going to combust.
Me, I am running my acer htpc hdmi into the hdmi in, and watching WMC live OTA through there, and streaming local media through Plex, or chrome casting it on the other hdmi port. Or using my roku.
There are a million solutions that don't involve cursing Bill Gates to the heavens when MS has nearly zero reason to support media center, much less the extender functionality which in 2005 was novel but never took off. Dead tech. I am sure there are a whole bunch of bullet points the Xbox one engineering team has to deal with, things that won't make it, things pushing to tier 2 and 3...WMC is probably at the bottom.
If you use media center, none of the above should be shocking. It is getting less and less support from everywhere.