This is something that has been emphazised on multiple times. The Wii U and 3DS version will offer the same content on both games except, essentially, they will not. This is what IMGMR writer Seif Mazzene believes the way they should treat the two versions of Smash Bros. 4.
Masahiro Sakurai, Creator and father to the Smash Bros. franchise, wishes to make the fourth installment of Smash Bros. on both 3DS and Wii U and that they can interact with each other in some way. We got the Direct video, the E3 Developer Roundtable and many Interviews, Sakurai is dead set on making the two version very similar, but still unique. Let us evaluate what is the pros and cons of this decision.