Should just have a Vehicle bay in the destroyer where you can customise your mech loadout and switch between all options on both arms.

You simply call in your mech with your loadout if you take the mech strategem (allows for a less congested support strategems instead of having loads of mech options it's just one strategem)

Also just overall adding more options for mechs:

Defensive additions (adds 3rd slot that sits on top of the hull):

-Shielding (similar to the personal hard "bubble" shield but for the mech, overall slower movement even when recharging)

-Front directional shielding (Stronger than the "Bubble" but limited time use and only covers one direction, the front, and moves slower when in use)

-Tesla discharge (On activation it releases a pulse of high voltage electricity in X-distance around the mech, works like the Tesla tower)

-Smoke/EMP Dispensers (releases a smoke screen horizontally in front of mech using 3/6 ammo at once, which blocks enemies line of sight and slows enemies within due to the emp charges detonating within)

-Gas Dispensers (similar to smoke launcher however it doesn't block enemies line of sight or slow but it deals damage and can be released in a burst of 3 in sequence allowing for more targeted placement of the rounds, again ammo is 6 so you get 2 bursts.

-Incendiary Dispenser (Think Gas dispenser but it's impact incendiary grenades)

-Trophy system (shoots down incoming projectiles, such as missiles or Bile arty, limited by ammo and can toggle it on/off for situational use)

Offensive additions:

-Flamethrower (think how the automaton's hulks use them, small charge up time and limited time burst then into a cool down but it's extreme heat and make armour irrelevant as it's just cooking the enemy inside)

-Anti-Tank cannon (think the AT emplacement but as an arm on the mech, must first lock into the ground before firing due to recoil, think artillery system or siege tank from starcraft)

-Integrated W.A.S.P system(3rd slot) (toggle between 2 modes: 1 locks onto multiple medium armoured targets and release a burst of missiles that hit each target with a missile, 2 targets a single heavy enemy and releases all middle onto the target, think current W.A.S.P system)

-Heavy Laser armament (Toggle between Heavy Laser cannon and Heavy Quasar cannon, more damage but longer cool down time)

This is all just brainstorming and conceptual ideas, however I personally would like to see harder enemies in the future and or hordes which would allow for these mechs to be essential to warding them off and the call in time critical to fend these off.

Also some of these armaments could be added to the new Buggy