In the end, I still want more combined arms aspect but how the heck they are gonna balance infantry ? Because mass infantry / savannah masters are among the most dangerous things in Battletech.
I had ideas for tabletop to change it up, but balance can be done by limiting the number you can field. After all, dropping infantry is theoretically easy - but logistically difficult. Say you can have up to four "Combined Arms" slots, a maximum two of which can be Vehicles, or four infantry. Or a Thumper artillery crew with a number of shots relative to how many slots you "burn" on it, or paying for aerospace support from your employer by trading a percentage cut? So at most you could drop with 8 units, 4 of which would be 'Mechs, 4 of the others being locally available vehicles or such from your employer.
Which means it would be in later-developed contracts and not ones from vanilla, and likely would be against OpFor assets which would warrant that sort of investment. (Unless contracts were rebalanced across the board, but that's a lot of work to expect. As much work as adding "quirks" or special equipment to all other 'Mechs which exist.)
And the thing is . . . how many different vehicles would people really use if given the choice? I'd wager they'd stick to PPC Carriers or LRM Carriers unless there was a specific cheesy exploiting build being done. Most everything else already in the game is kinda . . . well, not worth using from the player's side. I mean, the best vehicles you could get to them are either hovercraft and not in yet (bring me my Saladin hit squad!) or harder to get in the Periphery (Von Luckners and Behemoths . . . oh my . . .)
There's a lot of things which could be added, but the questions to ask aren't "
can it be done" but "
would it actually add something more than just another unit?" - often the answer can be "no". Even "Heavy Metal" wasn't immune here - if there had not been special equipment, would there really be a place for the Assassin or Vulcan in the game? The Flea? The Archer, Phoenix Hawk, and Rifleman I can all say should be in - they're some iconic things! But the trio of former 'Mechs just are additive for the sake of variety and not necessarily to do something interesting . . . until you look at the equipment. (And even then, not sold on all of those having much of a place.)
It's a personal opinion, but the first thing I'd add before combined arms are contracts which would have a reason to bring scouts or to focus more on speed instead of firepower. You know, a legitimate reason to take fast 'Mechs without inventing COIL beams... maybe higher difficulty missions which have stipulations for a timer instead of putting heavier units on the field? Maybe there's a tight drop/lift window so Sumire needs you to get the job done quickly before aerospace catches her (with the employer committing aerospace support if needed, at a -10% cost; a reverse of the +10% bonus for optional objectives?). Or maybe a test run of something in the future, where you can opt to add stipulations to the contract by . . . only dropping three 'Mechs, or only dropping under a certain weight class, to get a higher reward amount from the employer for being "more discreet"?
Regardless, I really would have tried to put development time into missions or prototyping ideas to give a feel that "just kill everything" is not an optimal solution 100% of the time. Maybe sometimes not even a viable one, no matter what you drop with. While I can come up with concepts for a while, though, most of them just are more suited for the custom-built Flashpoints instead of random-gen contracts which have to be more flexible and broad by virtue of needing to cover a great many bases.