Note - Many MMO's are better then WoW, but I wouldn't say maplestory is one of them. As someone that played it for yeaaars and yeaaars, the main gimmick it's got is that HEY IT'S A PLATFORMER but it really isn't, because there's rarely any meaningful issues that occur due to a lack of platforming skill. Aside from jump quests, but they seem more like they were added for the sake of proving that the game was a platformer guys, seriously.
Yooouuu.... might, try ragnarok online. I hear a lot about how it hasn't aged well, but I recently started playing again, and not only has it gone F2P (well, cash shop, but), but the entire stat system has gotten a renewal, and stat builds are actually fairly open as a result. (Can make a physically based priest for instance. You're probably not going to compete with anyone in PvP, but the game is far more open then a lot of MMOs out there, for better or for worse.) Being a Korean MMO it's fairly grindy, as a note, but it's better then it used to be. Annnnd perhaps it's best quality, the graphics are basically a series of animated gifs, and terrain made with 1995 3D modeling software, so it is VERY easy to run. You'd think the graphic quality would suffer because of this, but the game honestly looks pretty okay. PvP is okay, due to Guild War kinda things, annnnd monster combat is pretty nice due to MvPs (think boss monsters that will totally kick your teeth in without a party, barring borderline exploits).
Of course this all comes back to grinding as the main complaint, so if the thing she didn't like about WoW was the grinding, you may just skip that. :p
Maybe check out Dungeon Fighter Online or Mabinogi, too, both free, both korean, DFO isn't terribly grindy and is closer to a sidescrolling arcade beatemup, and Mabinogi is a "virtual life" thing. Not quite as in depth as Haven and Hearth, but the combat is nice (and easier to understand then HnH's to boot), and the gameplay does not consist of "wander into the wilderness and find berries", as it tends to devolve into later in haven and hearth. Crafting is fairly limited, mostly just tiny minigames, but still better then HnH in that respect. Mabinogi is honestly a VERY unique MMO, and I suggest you at least take a look at it. Pretty anime, but fun to play.
Dungeons are instanced on those last two, too, so the chances of some jerk coming in and ruining your day are pretty low. RO's chances for such a thing are significantly higher, but honestly not bad, I've never had it happen.
Why yes I do play a lot of MMOs what of it