One interesting way to buff miniguns a little could be to let players lean into the playstyle fully with a heavy electric motor item. This would fit in the other weapon slot (or some other active slot if it's more fitting) and would need power cells to charge. While it has enough charge it keeps your equipped minigun at maximum stacks of windup. Energy efficiency would vary between electric motors, and it could also become lower the more stacks of windup are active.
That's about it, talk about a reason to use Long Game and Slow Starter now.
