They might as well keep the clones. They take little effort to make and can appeal to someone with different tastes.

Example: I play Lucina over Marth because I prefer her blade dealing consistent damage/knockback and i'm not a fan of spacing. Also, I Main Dr. Mario because I don't like how Mario plays. I also just like Lucina and Dr. Mario as characters more than their counter-parts.

I don't really see a reason to drop the clones if they're just extra characters

Would you all like to see Banjo in this game?  Phil Spencer is all for it. 

This is kind of the problem with the Smash community when it comes time to predict Rosters. It's not that they want characters to be cut, but it's that it's been such a consistent thing since Brawl that they almost arrogantly focus on predicting which characters are going to be cut ... as if it HAS to happen because it's been this way before so it has to be this way again! I guess it's just a consequence of being so interested in rosters.

In reality, I think we're going to see the developers try their hardest to keep most of the characters. Cuts might happen unfortunately, I wouldn't be surprised if Square Enix took out Cloud so they could charge for him later. And I also think it's somewhat likely that Fire Emblem characters will be cut (and replaced). But I do think at this point, with a roster as good as Smash 4's,  it's really not necessary to cut much anymore.