What I fear is that if we get Marth, Ike, and Chrom I'm sure they'll be ignorant fans saying things like, "omg I totally love Chrom! It's so cute how Chrom is Marth and Ike's son!" Not that I'm saying that it's a reason to not have the three, it's just that, well, you can't avoid these things.
But yeah, even in Chrom's concept artwork, he bears a striking resemblance to Ike (looks like they had a little bit of trouble coming up with originality, no?). But hey, seeing Swimsuit Chrom kinda made me like the guy even more (Smash Beach DLC anyone?).