Ok so having played the first half of Birthright I wanted to share some thoughts on the game.
First of all, I like it a lot, definitely an overall improvement from Awakening. The game's cutscenes as well as in-game scenes are great and the world itself has much more variety and life to it that I couldn't help but instantly like it more than it's predecessor. The combat animations are great, as well as most of the map design (snow level I'm looking at you). Also, the changes on the weapon system made things interesting, though I can't say it's all good or bad, it's different and it will take some time to get fully accostumed to it.
Now, about the things I don't like. I'll leave the localization aside, as it has been amply discussed, as well as some of the voice acting (yes, I think Felicia's voice sounds weird, as well as some others, but that would be nitpicking). I think that the only thing so far that I really don't like is the children's mechanic. In Awakening it made sense because of the whole time travelling stuff, but in Fates it's just plain out weird. It doens't make sense at all, and it's not even something I can overlook after thinking about it for some time. I'm a guy who can overlook some plot holes when he's enjoying something, but this I just can't. It has so many plot holes it's ridiculous. The only thing I'm grateful of is that, at least until now (I'm at chapter 13) it's totally optional and not strictly plot related (again, not like in Awakening where you had Lucina telling you other children came back to the past, so it was kind of a major deal having to recruit the children, even if it was optional, for plot sake). So I guess I'll just not get the children, or at least not focus on them so much because I think their parents are already pretty interesting and likable characters. I actually wouldn't have minded children not being at all in the game, since the main cast is actually pretty solid. I hope IS doesn't return to this feature unless they can back it up in the right way, maybe doing a game with generations of characters, like in Genealogy of the Holy War.
That aside I'm really enjoying the game and I'm taking my time with it. I bought the SE so I have a lot of game left to play. I'm looking forward to it.. Definitely one of the must haves in the 3DS library.