I would be the first to criticise Autodesk, and I have in the past, but in this matter they have been open and transparent.
It has been well known for at least two years that MDT specific development will cease, and anyhow there is not much they can add with regard to functionality. On a good machine, MDT still kicks Inventors butt. All right Inventor is easier to model with, but as a design concept to death tool MDT is still better even with large assemblies, i.e. more stable, predictable, capable. I often compare MDT with the Lloyd of London building; it is an ugly brute and has all its bits hanging out, but at the end of the day it does everything you need of it.
The principal criticism I would make of Autodesk is that they have not made life easy for the MDT user transferring to Inventor. For example: Large MDT assemblies cannot be converted, unless you have a year or so free, nor can MDT assembly files be 'placed' in Inventor assemblies; there is no conversion path for MDT part or assembly files if you wish to maintain the drawing link, so MDT will be loitering around for a while yet. I could go on.
In my opinion it is best to continue updating MDT because they are adding backroom stuff that will make any migration to Inventor easier in the future, if that is your chosen path.