I nominate Ike, he has been the lord of two Fire Emblem games a feat only accomplished by Marth star of the first and third games. Ike's first game was released worldwide and his second one will be soon. He and his game are increasingly popular worldwide and he is by far the most likely Fire Emblem chracter (aside from Marth of course).
Some people think that there are too many sword users in Super Smash Brothers, while it is true that Ike does use a sword in Fire Emblem: Goddess of Dawn he also gains the use of axes. In both games he weilds Ragnell, a ranged sword. His fighting style is a lot more rough compared to Marth's fencing style as well.
Some people think that he looks to similar to Marth. Even though he didn't look anything like Ms Marth in Fire Emblem Path of Radiance anyway in Fire Emblem Goddess of Dawn Ike is a lot more manly looking and has big muscles, very different from the delicate girl like Marth.