I think he would be a great addition to the game and could provide a new unique playstyle as opposed to many other heroes. Even as a teamup only. He may not be a huge part of Marvel but I think something outside of the 'normal' superhero could do the game good.
'As Slapstick, Steve Harmon's body is made out of Electroplasm after exposure to an unknown alien device, which makes him indestructible. Any damage that he takes can be immediately shaken off, as he possesses superhuman durability and virtually unlimited physical malleability in the manner of an animated slapstick cartoon character. Slapstick also possesses superhuman agility and reflexes. It has been shown that the molecular bonds of the Electroplasm can be disrupted by a counter charge of a specific frequency of energy, reducing Slapstick to an immobile "puddle"; however, another energy charge can restore him to "normal".
In addition, Slapstick gets temporarily stronger when electrocuted. However, he must have a consistent feed of electricity to maintain this strength.
Slapstick's gloves also possess alien technology. His left glove has a transformation inducer that allows him to transform to and from Slapstick to his normal Steve Harmon form. His right glove is a materializer that contains an extra-dimensionally sub-spacial storage pocket, which functions similar to cartoon hammerspace, and allows him to store items seemingly nowhere. He can access these items by making a special gesture with that hand, though to anyone observing it would appear he is pulling them out of thin air. He usually keeps a large cartoon-ish mallet in this space. Recent accounts have shown similar pockets in the pants of his costume. Objects stored in these pockets are apparently undetectable by conventional means; for example, Slapstick carried his New Warriors communicator, left forgotten in a pants pocket, into Camp Hammond without any of the base's security measures detecting it.' - Direct from wikipedia on his powers. I can see a lot of potential with him.
Has there been any thought on him before? Really the only characters left in marvel I'm looking forward to are super skrull (whom I'm afraid will just be a taskmaster but with fantastic four powers) and Slapstick so Im hoping to get people to see him as a viable option for a new hero/teamup.