Check out dungeon fighter online. It's basically a side scrolling brawler, ala streets of rage or final fight from way back when. As a note however, it uses P2P, so playing with other people, unless they're nearby, may be a bit of hassle. So you and her playing, presumably from the same house or neighborhood should be fine, random people from who knows where, a little more shakey.
If she's okay with soloing from time to time, it is an excellent game, and in my opinion quite a bit better then Vindictus.
As a note, it still basically consists of running dungeons repetedly, but I'd still give it a shot. It's a lot more fast and furious then Vindictus.
Also if you're in the UK, there are no servers for it, but I'm pretty sure vindictus had that problem too, so you're probably fine.
EDIT: Also, the game is fairly slow in the beginning, and ramps up over time, so it should be pretty nice for transitioning to fast paced computer games. It gets pretty nuts later on if you play something based off combo-ing and the like, rather then tossing high damage skills around. Skills can also be triggered via button inputs like fighter games (like the monk has a skill that uses the hadoken motion, then Z), so yeah, pretty nice. I'd plug a controller in if you can, but it's fairly serviceable on a keyboard.
EDIT2: It also appears to be having some minor lag issues right now, but they'll prolly be gone by tomorrow. Nothing too terribly disruptive as far as I'm aware, but keep it in mind if you're trying it right now.