I've tried mutiple devices. Several Android devices, a Windows Phone 8, and my laptop using Connectify and Virtual Router and I cannot get the 3DS to use these connections properly. It kind of works, bu not fully. The connection tests are always successful and I can browse the e-shop, and such, but I cannot play games online. MK7 always get stuck trying to find other players. 

Am I doing something wrong or is this just an issue with Nintendo and their lazy and lackluster implementation of anything having to do with online gaming? Has anyone found a device that will successfully create a WiFi hotspot that will work with MK7?

Sounds similar to my network connection issues, which I believe stem from my router.

They more than likely stem from Nintendo, not your router =)

Ehhhh. The way I see it, messing with the settings of my router would fix the problem, while calling Nintendo and telling them it doesn't work would accomplish nothing, so to me the "cause" looks like the router.

Indeed. I had the very same problem recently where I was able to browse the eShop and all, but not play online multiplayer. I couldn't even connect with a few players on Xbox Live, so the issue wasn't 3DS exclusive.

Sadly, the problem wasn't solved until I got myself a new router.