Weird, I'm able to connect and enable remote play, but the viewer will display 2 frames of video before immediately disconnecting. There's also a warning about "disconnecting in 10 seconds" in the debugger, but it disconnects in a much shorter time than that.
Still, it's an impressive beginning nonetheless.
Edit:
Turns out to be the crappy router, frame rate seems much better with my secondary router, although video streaming only works on the Home Screen. Opening a game causes black-screening while returning to the Home Screen will resume video stream.
Edit 2:
Welp, my N3DS XL has now decided it doesn't like my secondary router. While I can successfully connect to it, as soon as I go back to the Home Screen and attempt to connect to it via NTR debugger, it defaults to StreetPass and disconnects from the router, preventing video streaming. Rebooting the console allows it to connect to the router, albeit for only a second before it returns to StreetPass mode.