What I hope ninty does is make Lucina an alt for Marth, Chrom an ult for Ike, and Robin as the 3rd playable character. It would make perfect sense.
Marth is a speedy character, Ike is a heavy hitter, and Robin is a Mage. So they fit the archtype tree of speed, power, and range.
As for competitive play, Ike got more spotlight in Project:M than he did in brawl. And don't get me started on Roy... I do not, DO NOT! Want to see Roy make a return