Eh, maybe when you account for Paper Mario and Animal Crossing as well. I dunno.
Can some of the more hardcore Fire Emblem fans rank their favorites? I've only played FE7 and I loved it, but I haven't played any of the others.
I won't rank them but here are my opinions on the others I've played:
FE5 - You can enter a code so everyone gets double EXP. I did that. This game is too hard for me even still.
FE6 - It's good. Support conversations started here so they're not very long. Still kinda hard. Accuracy is down across the board.
FE7 - The one I get nostalgic for. I wish more FEs would break the fourth wall like FE7 did. Designed to introduce people to the series.
FE8 - Really, REALLY easy. Also the writing is kinda iffy in some spots. But it had some cool gameplay ideas like branching promotions. FE13 follows this one gameplaywise.
FE9 - A little harder than FE8. Adds stuff from the SNES games like skills. Expanded inventory of 4 weapons and 4 accessories. Good story. Fun characters. Support system greatly simplified. Units can promote without an item, by reaching level 21.
FE10 - An unfinished game with good ideas. Follows FE9 storywise and gameplaywise. Support conversations removed, though supports are still in. Lots of chapters. Lots of units, but a more than a few are not around enough to be any good. You could tell some IS didn't have time to balance some characters and had to cut some maps. Easily the hardest one released internationally so far. AMAZING endgame. Most ambitious FE to date imo.
FE11 - Back to the very basics. Remake of first FE. No supports, but there are some bonus conversations. No base conversations. Marth is a sucky lord. No rescuing. But, I still enjoyed it. Cool music too.
FE12 - Sequel to FE11, but actually good. Characters have personality now. Base and support conversations are back. Create-a-unit, inspired by FE7's tactician. Tends to be pretty broken unit. Marth still sucks. Was designed to introduce people to the series, but was never localized. Translation patch coming out soon-ish.