I voted Eliwood as the worst. He sucks earlygame (lance users sure like to impale him), doesnt double reliably until promotion mediorce caps and growths and gets a crappy legendary weapon.
The best is Ephraim, sure his caps blow but at least he can reach his (looking at you Eliwood <_< ) plus he gets lances and rapes as soon as you get him.
idk why some think Lyn is bad, at least she can dodge and she doubles at base level. When she promotes she is a dodge tank!! Her growth spread is good. (I think her bases somewhat suck but thats another topic for another time)