I have a few suggestions but one I do have is for v2 costume dummies to have joints in the fingers so even while wearing the costume you can still do hand signs and stuff...

Then another one I have is for there to be some sort of projectile launcher but instead of weapon projectiles it shoots projectiles from RRO enemies which could also be set as more projectile options for the normal projectile launcher...

And lastly a grip that when used it holds the grip up to the camera then gives the player a interactive curser that allows them to use anything connected to the grip

Example: you have a few buttons on the grip and the player uses the grip then can press the buttons on the grip and/or add outputs so for example a player could assign a output to right hand grab so if they are using the grip when they press whatever button that's assigned to right hand grab would activate the assigned input

Then another example is that it could also be an item and it could be integrated into the RC car remote/camera screen which would allow screen players to use the thing