Huge ammounts of new :
- weaponry (new and bigger AC's, rockets and lasers, chain gun lasers, mortars/artillery - takes time to setup, immobilizes you)
- melee weaponry/melee fighting mechanic (now this is a big shot... but what the hell we all can dream and hope

- gief atlas boxing gloves!)
- equipement (combi engines that are kind of like clan XL, you can get your torso shot off, weights more than regular xl but less than std, takes slots on side torsos, faster than std, slower than true XL's), augmented mechanics, reduced power down time equipement, auto-loaders placed next to weaponry to reduces uac jam chance, damage or range, engine item that increases torso twist speed, side boosters that can help you decrease speed quicker/turn left/right quicker, accelerate faster)
- consumables (maybe additional ammo packs carried around in consumables slot? AC users would definetly jump on that one)
- ammo types (which you can switch around in game, but should take some time before you are ready to fire again after change)
and semi omnipod mechanic for any non omni mechs so you can try different things with same mech (its like a car you, should be able to swap around any stuff, it just takes time, cash and effort).
Definetly would fool around with quirks to pods and/or buff/change up (drastically, with bigger numbers) existing ones.
Black Jack Arrow is a beautiful example of amazing quirk (+30 Rate of fire on machineguns?) which defines the mech.
I wish there were more mechs like this. For example Mauler with +50% reduced uac5 jam chance and 30% reduced cooldown, etc. Numbers are outlandish but they are meaningful, whilst quirks in general atm are just there... and in most cases your feeling about them is : whatever.
There are tons of modules that could help and customize and give players the ability to have actual unique builds.
You want to pew pew away here are modules that go beyond stupid cooldown/range tweak. And on lowered gxp and c-bills price (cut it like in half)
These are just but a few quick examples :
- Uac5 -20% jam chance decreasing module
- AC20 velocity buff (bullet flies faster)
- any range module should also have small increase in projectile speed (although dedicated projectile speed buffing module should do it 2x better than range+velocity speed)
- LBx10 -30% spread decreaser
- Heat decreasing modules for specific weapons,
- damage increasing ones,
- srm quick loaders - chance on shot to have either jam or instant cooldoowned srm weapon so you have a chance to double tap srms,
- srm becomes target pointer following semi guided missles have longer range but increases cooldown significantly
- module that increases your speed when changing ammo type in your weapon (like smoke rockets, blind/flash rockets, armor piercing bullets to your ac which would deal bonus dmg to armor but reduced dmg to structure and explosive ammo which works the other way around),
- module that would pump your engine speed like a secondary speed tweak,
- module that would increase your torso twisting speed so you won't have to get that huge engine to twist effectively
- additional armour module (for example additional 1 ton of CT armour - each additional ton slows your mech by x% should be exponentially increasing and really discouraging to put any additional armor, increases heat... whatever balances this out),
- module that switches clan ac/uac to be one bullet shooter
- is module that switches it to clan like 3 bullet shooting
- laser duration decreaser
- module based expansion to get additional hardpoint slot (e.g. module that gives you +1 ballistic hardpoint - ofc as long it is possible like atlas wont have 3 ballistic slots on right torso .. but if you have only one on your specific variant this module unlocks the other one bcs we know there is a variant that has 2 ballistic slots or like 4th missle slot for Atlas D-DC)
After we got those juicy new mods to toy with... each mech needs at least one more slot.
btw things like ecm/beagle/console command... should all take 1 slot and 0.5 ton i mean ffs you wanna tell me future computers are taking your whole goddamn room to fit in? gimme a break.
Being able to toy around with many different things would expand this game significantly IMO. And those aren't some radical changes. Would just need a very careful look and instantanous response with daily patching to remove OP'ed combination of module stacking. But keep in mind nerfing to the ground is always a bad choice. We want more toys to fool around with, bcs building a mech that suits your exact playstyle is a big chunk of the game. Playing its just an icing on a cake, an execution of cautious planning and building towards certain goals.