A shuriken cannon that fires millions of little ripper like projectiles, replace the minigun with that,
Or i have a pretty good solution to the mellee wepon thingy, lightning claws, their kind robotic energy gauntlets, they allow you to send out a shock wave knocking back nearby opponents, whilst at close range you can get a near instant kill by electrocuting your opponent star wars style(like that thing the emporer does)
aswell as that, the claws would allow you to deflect incoming shots/reflect enegy weapons. also the claws could be used to magetically pick stuff up/ attack your self to the back of vehicles to hitch a ride,
they would have a bunch of other use aswell!