If you could fix it somehow, what would you do to "fix" or "update" Classic Traveller to keep it more relevant or playable.
Sure ask a loaded question....
Or, haven't we been fixing CT for forty years already?
In that under CT there are a bunch of different Modular Bits we have been switching in and out of the core rules since day one.
MT was just another set of bits to switch in and out as well. Or to be Clear MT is just Advanced CT with a huge editing problem.
With that I generally think the special duty roll in MT should be added to Basic character generation. Though a viable point buy system wold be nice as well.
As an adjunct to the above, DMs for Atribbutes? And related Zero Level skills? I for one have given out/allowed many more Zero Level skills over the years.
Combat is another set of modules, I have used a flavor of Snapshot/AHL/Striker over the years. YMMV...
As for Ships and by extension vehicles, Here we get into the weeds. First off for ships there a two competeing combat paradigms, Book2 where Missile are the main battery, and Book5 which is much more shooty. Or, in another description Book2 ships are more like Aircraft and Book5 they are more like pre-aircraft Battleships. As such a design system for both is problematic.
For the record there are a number of threads on reconciling Books 2 and 5 already.
Also there is the question of whether you prefer a Big vs Small Ship universe.
As for vehicles right now I generally us the Creature Chart for them and Robots and assign attributes as needed.