IntelliHeath
As in "Heathcliff"
My choice for Lyn really has nothing to do with boobs. I'm a fan of the series and I don't see her as that. The FE series has many unique characters and I think she would be a great, unique, familiar choice. It's more of the fact that she has relevance to FE fans who started and enjoyed the series from FE7 onward. I agree that Ike was a better choice. She's also a different and unique type of Lord like Ike and wields Mani Katti which has more possiblitites for a moveset. There's also the added fact she can wield a bow which can even add more to her dynamic. I would love more female characters and I'll admit that but they have to be more than just a pair of tits, imo. I think Lyn has more potential than that.
I would like to mention that I would rather to see other swordsmen to get in over Lyn for now.
Those swordsmen that I would like to see (if all characters would return from Brawl.)
Takamaru
Shulk
Isaac/Matthew/Felix
Roy (He was planned to be in Brawl so I don't think they would give up with Roy this time but who know)