At the Audio Developers Conference in London, plans were unveiled about forthcoming features in the proposed new MIDI specification. The conference is hosted in conjunction with JUCE which is an audio application development platform that was recently acquired by ROLI - so it makes sense that any new specification would include features that make the MPE control format more integrated.
In a talk given by Ben Supper of ROLI and MIDI.org (the juicy bits start at around 12 minutes in), several new features are outlined. As Ben states, exact details are still a bit vague - given the amount of cooperation and interested parties and commercial interests involved. Which does make one marvel at the achievements of the original designers and diplomacy involved with the setup of MIDI back in the day.
Ben does point out that this is a prioritised wish list more than an absolute set of guaranteed features. Obviously with so much R&D and $$ invested (he says $billions) in the current specification, to change it all up is a monumental task which needs to be synchronised between all participating manufacturers ensuring compatibility with the original MIDI 1.0 spec to avoid older gear becoming obsolete.
Main MIDI HD Features (preliminary and not set in stone)