I know Ephraim's and Celica's DLC have good postgame maps and some of the nicest looking redesigns (imo) but nothing else. And then Ike's redesign is terrible but comes with the godly Limit Breaker skill. But if I don't plan on getting any Series 2 DLC like the Strongest One (I think that's in Series 2) then Limit Breaker is kind of unnecessary, right?
So if there's no reason for Limit Break, is the pack worth getting just for Ephraim and Celica or should I just save my money?
I actually don't like this series that much aside from Ike and his limit break. I prefer Ephraim's spotpass character to his DLC character, too. Spotpass version has Rightful King as a skill while DLC has Conquest, and I think Rightful King > Conquest.
And I don't know Celica as a lord or a unit so she didn't do much for me either.
That being said I still threw Nintendo my money for the pack because Fire Emblem.
It's a PoR map that made me hyperventilate. Which I count as a plus. Nostalgia!
It's also the first DLC series that features enemies stronger then the end of the game. But it sounds like you're only interested in the characters? They have useful exclusive skills and I did like the conversation with Ephraim after you beat his map but whether that's worth $3 to you may vary.
After all, if you managed to recruit them, you have an endgame capable team already and you won't need to get stronger then that if you're not getting season 2 DLC.