I feel exactly the same about my 3DS. I only have two games for it; Ocarina of Time 3D, and Mario Kart 7. I bought Super Mario Land 3D, but sold it after beating all the "main" worlds, as I thought it was incredibly overrated (it's a good game, but lacks any real imagination/creativity compared to most other Mario games, especially the Mario Galaxies). However, the thing that disappoints me most about the 3DS is the system itself; the battery life is abysmal, I find it generally uncomfortable to hold, and the screens are too small. For those reasons, I simply don't enjoy playing it much, even though I have tons of Ambassador/Virtual Console games.
The DSi XL spoiled me, and the 3DS failed to live up to that. The 3DS XL looks like it will be a carbon copy of the DSi XL, which is fine by me. Also, I've pre-ordered Theatrhythm: Final Fantasy, as I enjoyed the demo, and it's quite cheap. I now can't wait until the 3DS XL is out, as I think I'll finally start to enjoy the system.
I'm selling my DSi XL on eBay now, and as soon as I get the 3DS XL and transfer my downloadable games to it, I'll be selling my original 3DS. I'm hoping that those will both cover the cost of the 3DS XL completely, or at least very nearly.