Here's an idea though, what about transforming weapons?
I don't play league so idk what this is from but something like this would be super cool to have on a mech.
How I imagine the whole thing working in Em-8er is the weapon is usually a "hammer in this instance", but there's an ultimate ability for the hammer. which gives it a boost in speed, power, and range, maybe? but then also transforms the hammer into a new type of weapon which allows you to fire it like a one time ultimate laser move for bosses. or maybe even strengthen the power of the hammer so it uses the jets on the back to hit a lot harder and do crits more often.
This could be used for guns as well, transforming them temporarily into stronger versions of themselves of different types of weapons. In Halo 4, the gun called the Bolt Shot could be used as a shotgun if the shoot button was held down. The pistol would slightly transform its shape to accommodate the action.
regular Bolt Shot ☝
Shotgun mode Bolt Shot ☝
I'd love to see this feature in late game guns as a cool rewarding effect to pulling a power move on an enemy or in pvp.