Man, I don't know a lot of DS games are non-hardcore.
Mariokart and Metroid Prime Hunters are pretty good games.
Eh, they don't have to be "hardcore" for me to like them.

I have Mario Kart 7, so Mario Kart DS becomes kinda redundant. I've played Metroid Prime Hunters before...but I think I'll add it to the list. Never beat it.

new super mario bros
super mario 64 ds
okamiden
mario kart
sonic rush
mario party ds
mario and Luigi bowsers inside story
NSMB DS: I thought the original DS NSMB wasn't that great?
Super Mario 64 DS: I've played the absolute heck out of Super Mario 64 and Super Mario 64 DS. Had to have beaten the game at least four times. xD
Mario Kart DS: See above answer to quote.
Sonic Rush: You know, this totally slipped my mind. The game seemed like a good time, just never picked it up. Added to list.
Mario Party DS: I...eh. I like Mario Party, but the real fun of that game comes through multiplayer. I do enjoy the single player modes though. Added to list as well.
Mario and Luigi: Bowser's Inside Story: This is an RPG, but I do kinda want it. Added to list, but it'll be a very low priority in terms of first-purchase.
Advance Wars: Duel Strike
Trauma Center: Under the Knife
Tetris DS
Contact (It's an RPG, I know you said none, but if you ever get around to it, it's quite unique)
Any Mario Game
Okamiden (eh)
Time Hollow
Hotel Dusk
I loosely recommend Another Code: Two Memories/Trace Memory
--x--x--x--x--
Sorry I can't be much help since I'm an RPG head. When I can think of more, I'll get back to you.
Also, out of curiosity, I understand TWEWY, but I see Ghost Trick on your list of owned games.. so why not try 999?
Also... I see Maplestory thurrrr...
Let's address your game list first.

Advance Wars: Duel Strike: I thought this was an SRPG series? Either way, I'm not really into tactical stuffs, so no-go for me.
Trauma Center: Under the Knife: You know, this series completely slipped my mind. Added to list.

Tetris DS: I can't say I know how Tetris even works, so I'll have to pass. xD
Contact: I won't be adding this to the list, but I will check it out.
Any Mario Game: Hurradurradurr.
Okamiden: I've noticed this was on several lists on this thread, and a few of my friends have said it's good. Added. :V
Time Hollow: I've done a bit of research...strong maybe. Not enough to add it to the list, but maybe.
Hotel Dusk: :faceslaps: How did I not list this? I even thought about it, and I didn't list it. Added to the list. xD
Trace Memory: See Time Hollow's answer.
--x--x--x--x--
Thanks for sticking with me?

The reason I don't want 999 is that I'm personally uncomfortable with the amount of profanity they throw around in-game. That may sound stupid to a lot of people, but that's just how I am.
Yus, MapleStory. I really should get rid of that from my Fandom...I haven't touched the game in a couple years. :T
Chaotix: The Yugi-Oh games for DS were quite fun and worth keeping.
I honestly do not care for card-games...or Yu-Gi-Oh for that matter. Sorry. :T
AndyG: Animal crossing:Wild world
Never played Animal Crossing before...maybe I'll give it a shot. Added to list.
Answered in the quote.
You don't have any Pokemon games? 
It's not that I don't like them, I just haven't bought any in awhile. I'll probably buy one once they make a 3DS one.
Wow your three limitations effectively rule out anything I can suggest haha. Especially since you already have Phoenix Wright...
Have you at least tried out the games you say you're not interested in to be sure? I forced myself to with the FPS genre.
Okamiden and TC are already mentioned... How about... WarioWare or Harvest Moon?
First part o' yer post: I'm just not that interested in them. As I said before, I'm not comfortable with the amount of profanity in 999, and TWeWY just doesn't really look interesting. I'm sure I'll give it a shot at some point, but it seems expensive for something I'll have to spend a good bit of cash on. :T
Second Part: I do like WarioWare, it's just that I don't buy them because I'll play them for six or seven hours, unlock all the minigames, then get bored. :T As for Harvest Moon...I'm not that heavy into farming/life sims. :T
The Megaman Starforce Games
Lunar Knight(or Night... forgot)
Oooh Oohh! The Digimon games. I think they were called Dusk and Dawn? Not sure.
Every Sonic Game.
I tried a demo of Megaman Starforce...I didn't like it. Especially compared to its predecessor series, Megaman Battle Network. :/
Lunar Knight: It's an RPG, so while I won't put it on the list, I'll keep it in mind.
Digimon Games: I'm admittedly not that into Digimon. I know it sounds hypocritical seeing as I like Pokemon, but meh.
All Teh Sonic Games: Well, I know there's the Sonic Rush games...but what other GOOD ones were there?
@Above Post: I played the heck out of Kirby SuperStar Ultra. However, I haven't tried Canvas Curse or Mass Attack yet, admittedly.
I am curious on how Chibi Robo Park Patrol compares to the original Chibi Robo, is it any good?
It is a worthwhile title, but I don't think it's as good as the original Chibi Robo. Fun game though.
Posts that had nothing but repeat games from other posts don't get quoted. Not trying to be rude, but there is a limit to how many quotes you can have in one post.
And thanks for all the feedback! Didn't expect to get so many replies. xP
Edited by GameCollector, 09 September 2012 - 01:02 PM.