This has been on my mind for awhile. If you could choose 1 character to replace for Isaac in Brawl, but that replaced character would get in Smash 4, who would you choose?
Me, it would be Olimar. Now, I have no hate for the character whatsoever, but his inclusion in Brawl has always made me scratch my head wondering, "why?" Now, he would have been a perfect fit for Smash 4 due to all the weird, yet clever characters that were added like WFT, Villager, Duck Hunt, etc. Olimar fits better as a Smash 4 character than a Brawl one.
And if Isaac was cut from Smash 4, the reason would be, "...uh, his Psynergy was difficult to implement in the 3DS." HA!