One thousand percent with you, man.
PoR contains a "coming of age" kind of storyline where Ike basically learns everything about combat, corruption, racism, loss, etc. He's simply a boy learning to be a man, warrior, and leader. His stat growths are also higher than most of his friends, so he's a solid unit as well.
Micaiah, however as we find later in the story, is actually not a teenager. She is older than she looks, yet is painfully naive. She was around during the war in PoR, and probably was around during the time Ashnard slaughtered his family and rose to power. She has witnessed much more than Ike and most of his friends, but she still lacks emotional maturity. To add to this, she doesn't contain the SPD stat PoR Ike does, so I never even bother training her up without BEXP. Also, she complains whenever Sothe mentions Ike, and it makes me mad. :)
When Ike appears in Part 3, he is no longer a boy. Some can argue that he is too perfect in personality to be considered interesting, which isn't far from the truth. But I think that a lot of people are simply missing the point. Ike is now a hero, both ins class and in Tellius-status. He now leads a group of mercenaries that he has grown acquaintance with has attracted the attention of the antagonist(not villian)Black Knight as a great swordsman. Who is identical to RD Ike in PoR I wonder? Uhh... it's Greil, his father. What I know from PoR: Greil was a great man who treated his friends like family, and his wife (Elena, methinks?) was a woman of great compassion and understanding. Ike is clearly being portrayed as someone who has grown up and turned out to be much like his parents. More proof of this, Ike's physical appearance looks significantly more like Greil in RD than in PoR.
Micaiah is boring and I just use Edward and Nolan for Part 1.