Maybe as an assit trophy, Sure he has some moves that would work well such as the canon gun, crown throw, anything from DK64, hell he could use Clubba's club. There is tons of things you can do with King K Rool. But there's so many other choices that could work well. What makes him more viable than alot of the DK cast other than being the most well known antagonist, Yeah its certainly marketable but but Daddy Sakurai would rather surprise us with a different DK character unless the masses want King K Rool.