Just got the game and haven't played too far yet, although I have been watching some of the YouTubers. My thoughts on Gameplay changes to better balance mech classes:
Current Game
I would prefer to see balancing of mech types (light vs. medium vs. heavy vs. assault) handled through the economic engine via increased upkeep for larger mechs and/or harder to acquire new mech types, rather than hard-coded tonnage limits (in the campaign). To help balance player style, these changes could be on difficulty sliders for the campaign to better suit individual player preference.
Potential BATTLETECH 2 Changes
1.) Increase the mercenary group to company size of 12 mechs, but restrict the deployment potential of the player. Give them 1 Leopard dropship (one lance capacity) and a cargo dropship to carry the other 8 mechs in storage to the surface. Because the cargo dropship cannot combat-deploy mechs rapidly, your actual combat drops would be limited to 4 mechs at a time, although it would be possible for the Leopard to make a second run for reinforcements if necessary. The economics of the game would mean that running 12 assault/heavy mechs would be basically unsustainable financially.
2.) Add Operation-style contracts that involve multiple individual missions, either sequential or "simultaneous". Some of those missions could be more scout/recon missions where faster mechs covering lots of territory quicker would be advantageous, and the player could play hide-and-seek with the enemy to identify static/mobile forces while not necessarily having to destroy them. That might lead to more of a base attack mission later to deal with the identified defenses. Or a garrison mission might result in a raiding force making simultaneous raids on more than one target at the same time. The player would have to make choices of how/when to respond. Do you send your two heaviest lances to take on the biggest threat(s), while a more mobile lance (light-medium) fights a delaying action until one of the other lances is available? Do you sacrifice one of the raider targets to concentrate your forces? All kinds of possibilities.
3.) The operation-style contracts and multiple individual missions could also make ammo constraints/logistics a more important choice. Some of the YouTubers have clearly modded up their lances to have 2 or 3 pure LRM missile boats with 1-2 "tank" spotter mechs, and blow through the missions knowing that they are not likely to run out of ammo. On a purely personal level, I don't really like those sort of drastic revisions to mechs, feeling that it is not really in the spirit of the 3025 Battletech canon (these are not Clan omni-mechs where everything is hot-swapable). I completely get that this is a game and that everyone likes to play differently, but if you had the possibility of having to run multiple missions without resupplying in between each time, people would have to reconsider the balance between energy weapons vs. missile/ballistic weapons, including stripping out armor on a missile-boat mech you "know" isn't going to be on the front line.
Anyway those are my thoughts.
Mike