I'm not a fanboy of any of the 3 companies, but Nintendo has stolen a few ideas too Remember how Rayman Legends allowed a player to put a certain Ubisoft figure on the Wii U Tablet? Well, ever heard of Skylanders (Which came out in 2011)?
Also, Super Smash Bros wasn't an entirely original fighting game. Ever heard of The Outfoxies (1994), and Poy Poy (1997)?
Not Stole in first case, more like making an 'optional feature' if someone want to use it.
2. Outfoxies?Poy Poy? i don't know how related to Super Smash Bros besides being a 2d multi-men battle game, Smash bros is a Mascot Fighter who now one have make(maybe MvC but that count as a tradional fighter instead)
I'm talking about gameplay wise. Smash Bros has Outfoxies' camera movement, 2D gameplay, and hazardous arenas. Poy Poy has the 4 player modes, and items (I can't remember if The Outfoxies had items too, though).