Although having our mechs in their current configuration would be nice and I would look forward to that, admittedly bringing everything current would be the logical thing to do in development. :/
On that note, people who spent actual money on custom chassis parts will definitely be expecting loads of MC restored to their accounts - as well as MC spent to unlock weapons that may no longer be part of a specific mechs' load out. Its one thing to decide if you're going to use MC or HC to unlock a weapon, its another to spend MC on said weapon only to have its existence on that mech then revoked without compensation.
Although a unified experience makes sense, letting players keep what they have would be the safest way to 'shut them up' and move forward. No matter what approach you take to compensation, they're going to have to contend with people who are not going to be accepting of it and may bring the games reputation down. The server problems, delayed releases, NDAs, shaky acquisitions, broken timelines and inconsistent communications have passed so far with some skeptic eyes and abated breath. If they go forward and yank everyone's stuff, bought with money they spent assuming they were supporting this game, it could be really bad.
Or maybe it wont be anything at all. Personally, i'll be disappointed and probably wont spend anymore money, but I wont quit the game or badmouth it to new players.