My problem with Zelda was that dungeons were too short and there was a lack of searching and discovery because too-early in the game you're a walking arsenal with all the puzzle solvers on your person save for the items you get in the sand temple + Sand rod. This is not saying that Link Between Worlds isn't worth the $40 or your time, I just think in alot of ways it doesn't live up to the original. One dungeon is just a line. I'll admit the 2D mode adds an extra puzzle mechanic, but I never thought it was anything more clever found in something like Link to the Past.
Fire Emblem is more or less perfect, though not my favorite. By perfect I mean that I can't think of anything bad that would make me second guess my purchase. Alot of game restarting though...
Bravely Default has a demo, its beautiful with high presentation values, I'm just not a fan of the overused and stale turn-based RPG battle system of waving your hands in the air and constantly mash a single button to make monsters go away and grind.
Luigi's Mansion 2 feels too short. Classic Nintendo game making, they make something amazing, but fail to take it all the way home leaving you kind of feeling "Meh" at the end of it. However it's the more unique of your choices. Its like merging 3rd person adventure with point and click, you simply haven't played a game like this on handheld, period. Much improvement over Luigi's Mansion which was already quite good.
Zelda: A great title to own but feels shorter despite having more to collect.
Fire Emblem: The greatest value in terms of Gameplay for money.
Bravely Default: Its an RPG from Square... again... Meh, get it if you haven't grown tired of basic RPG mechanics of the last 2 decades.
Luigi's Mansion: Most unique, possibly most beautiful, most charming, but feels like Nintendo missed an opportunity to truly make this game a legend.
I'd say get Fire Emblem or Luigi's Mansion, personal choice being Luigi because enjoy fresh experiences, Bravely Default IMO can wait, and you're probably going to buy Zelda eventually so its a matter of buying it now or later.