Nanite repair bay. For defense-centric builds. The gained HP each turn is tiny, especially compared to the repair kits, but now it's all the more important to press your damage dealing advantage over mechs built for a more long term battle.

Melee grappler arms. Get in close and grab your opponent by the face. Maybe a percentage chance to wiggle free with movement while teleport is immediately successful? If the grappled mech has their heat or energy shield active it deals electric or explosive damage each round?

Repair drones. Drones are almost entirely made to whittle down defenses or HP as quickly as possible as a psuedo third turn offering little benefit to defensive builds. A repair drone that repairs a small amount of HP each turn, increases energy regeneration, or passively bleeds off heat would give more defensive mechs a reason to rethink their builds and set aside some weight for a drone.

Hacking. Obviously if the mechs can control an external drone they have some wireless networking capabilities. It only makes sense that could be hacked. This could create a whole new sub-layer to the game play to consider when building a mech. Working up a digital defense as well as a physical one to avoid having components shut down or drones stolen or setting up a digital offense as well as a physical one so you can shut down an enemy's more dangerous aspects while thumping them with your best weapons.

More damage types would be great! Magnetism, acid, and microwaves all play havoc on electronics and machinery as much as foreign electrical currents, physical damage, and explosive damage. That and acid would could add a damage-over-time effect. Those are always fun.

Just a few thoughts. I've had since beta.

I quit playing a long time ago and when I came back I saw the swords and immediately fell in love with the game. What's better than giant fighting robots? Giant fighting robots with swords!