Clicked that article thought it would be worth quoting one of the IGN user's comments
"It is the same general sub genre of game yes -- but that's exactly what it is. The similarities to Smash Bros is undeniable, but that's because THAT IS THE GENRE, it's not a Smash Bros ripoff, it's just another entry into the genre that was popularized into the mainstream by Smash Bros (don't forget there have been many other games similar to the Smash Bros style in the past, recently and before Smash Bros as well).
It's like saying that every First Person Shooter is a cookie cutter copy of Wolfenstein 3D.
are they similar? yes, but that's because they're part of the same sub genre of games, of course they're similar! The only difference is that the sub genre that All-Stars and Smash Bros fits into hasn't been exploited/explored as much as other sub genres like FPS'."