Hmm, thte toal rewrite or super far jump ahead is appealing to me more, but I think I'd favor the super jump ahead so the old stuff could remain official and out there for those who wanted to stick with it.
Avoid/Undo so many problems..like never really detailing where factories are, where parts are made. Just name companies with myriad productin facilities at all key transportation hubs. There, less stupid facts to keep track of that add nothing to the game except a headache when someone complains that widget X is only made on Planet Spaceball. No need to waste the effort tracking pointless trivial details.
Cut down faction tracking. A few houses, and handful of Clans, good enough .I can't keep up with the worings of Clan Trunkmonkey and its conflict with the Republic of Bellybutton Lint on the Periphery.
Advantage two: gut the existing number of 'Mechs and vehicles. Redefine TRO concepts to be fewer machines, but more entries and art on variants. Eliminates overlap, needless duplication, and shelf space bloat on the miniatures line. (But make translation rules for those who want to play old outdated antiques or retrofittedAncientTech) go with an initial 75 to 90% reduction, then slowly build up to maybe 30 to 40% (tops) of the current size, then phase out obsolete designs in fiction for every new one brought in.
No matter when the retcon happens, it retroactively forever alters the Unseen images to new art. Old Minis are welcome at the table, but with the understanding in canon thats never how they looked, you just happen to be fielding a heavily modified or frankenmech version of the 'mech. Stick a fork in the issue, its done, and not worth a second more discussion.
Kill Warships. Kill protomechs. Make the strategic level of play far more palatable and common. (Not that i'm biased or anything.) Mechs uber alles in fiction and gameplay.
Change tech bases for mechanical gameplay improvement. No cluster charts, easy to do battle point system, modify or eliminate the hit location/ ciritcal hit process to speed up damage resolution, vastly simplified construction. Heck, I'd dump the current skill and 2d6 system for something more intuitive and flexible. d10's/20's are ok with me.
Or just clean up the fiction and make minor improvements. I'm not unhappy now, just realizing we coudl make things better. Change will upset some, and lose some players, but meh, fear of change and losing a few customers means you never gain a wider audience and doom yourself to a dead end in the long run. Grow or die.