\"Killer app\"s for the DS ?

Recently I became a proud owner of Grand Theft Auto for the GBA and although I only played it for about 15 minutes, it appears that I finally stumbled upon a GBA's "killer app".

As far as I can tell, there is no "killer app" for the Nintendo DS.
However, when I think about this, there are a couple of suggestions that come to mind that would make me buy one instantly.
Unfortunately, I know they will never be made.

1) Fallout (1) for Nintendo DS. Pure digital sex. Maybe make it overhead view instead of isometric because theres only so much real estate that can fit into 256x192 resolution.
The touchscreen would be perfect for management of the dozens of buttons and stats.

2) ELiTE for Nintendo DS. Yes, there is actually an ELITE for Gameboy Advance, but its an unofficial project that requires the use of flashcart, and it uses "original" vector graphics.
ELITE for Nintendo DS could use at the very least plain shaded polygons, in addition to the touch interface.
If you don't know what ELITE is, think Privateer 1

3) Warcraft 2 for Nintendo DS.
Advance Wars can go kiss my keister.
"The submarine can only fire from water at this specific unit which in turn can only fire at this specific unit but only if the weather allows and if the Moon is in the retrograde".
Screw that.
Give me Warcraft 2 or give me death !
... wait, just give me Warcraft 2.

What would be your ideas for a DS killer app ?

Wario Ware Touched, Animal Crossing Online (visit other towns via internet + voice chat), the Squeenix/Nintendo Online Collaboration, Metroid Prime:Hunters 16 Player Online, Goldeneye 007 16 Players Online.

Plus the unnamed RTS in development.

Next year is going to kick ass, I''ve only mentioned a couple reasons to look forward to the DS

a new metroid side scroller
a new castlevania side scroller
a new zelda (like LttP)
a good old skool turn based RPG

Any of those would be a killer app for me.

[edit]
I dunno if any of you remember an old NES game named ""Crystalis"". It was rereleased for the GBC at some point, I think. In my opinion, that would be a good candidate for some sort of DS remake.

They definitely should produce some more strategy game or business sim titles. The stylus works really well for games that usually rely on mouse controls. For instance, Sim City for Palm OS is as much fun as the original version. Whereas the lack of a proper input device certainly hurt the SNES version of the game. Such games certainly won''t be killer applications for everyone, but it''s something the the PSP or the GBA can''t compete with due to the nature of the hardware. Animal Crossing or Pokemon with WiFi and Online support, however, should go very well with the mainstream audience.