I've always thought it could be just a tad better. If nothing else, it should grow depending on the size of the stage. Yes, Dojo is a given clean up. But if I'm on Black Rock Stadium you can forget about getting mainy kills at all. I'd be fine with any sort of slight buffs but ala Ice Climbers Final Smash from Brawl, it should adjust to the stage size.
Btw I been in a lot of 2v1s lately...
I guess its good practice because I'm use to running and finding little openings. And I actually win most of my 2v1s now (Unlike in Snash were you're most likely **bleep**ed) and their reactions are priceless on the mic xD
Also you shouldn't be going for Cole's level 3 in large maps.
Or, they could leave the timeframe as it is and make it to where the tornado will launch some of the debris caught in it to either side, making it harder to dodge and giving it a little better of a chance to get 4 kills.