personally I would like to see Vulcan return just to get into it with Matthew Malloy. If malloy can tap into some crazy unknown power source (which I would say is safe to assume is energy) then Vulcan may just be able whoop him like he should be able to do anyone else.
if his powers are to manipulate all forms of energy, and malloy is supposedly above omega, the shouldn't Vulcan be above omega? manipulating energy is kind of God-level stuff.
just my opinion
I would also like to see him return to be a father and not be a complete tool :)