I plan to move to SNES homebrew and even Playstation 1 homebrew once I'll have successfully released several good NES games.
However, that won't be before a good while.
As for tepple's list of problems :
a) isn't a problem when you already know like 6 different assembly languages. Just print the instruction chart in doubt
b) Finding WAVs is not a problem, but making them fit the restricted SPC memory might be a problem. Anyways a low quality/small soundfont should do the work. Or just rip samples out of SNES games

c) Is definitely true ! However you can always come up with cheaper graphics that don't push the system to it's limit. It's the main problem for me, who is a very mediocre artist.
d) Not really. Layer 0 = playfield, Layer 1 = parallax or transparency or large bosses, Layer 2 = status bar and textboxes. Or if that's too much layers, use 2 layers, and use the tile-per-offset in mode 2, an amazing feature that was way too much underused
e) I don't see how it is "hard" to use 2 Megabit. You can always start with an almost blank 2 Megabit ROM. Uncompressed 4BP graphics will take up space quickly, and 64kb of SPC samples will already take 25% of that space.
f) Well the Super Power Pak and other similar devices exists for a reason.
g) I don't know much about SNES hardware but I doubt you have to use DMA, you could always manually copy the CHR assets in forced blanking mode.
h) You can code in assembly, although it's not quite as convenient.
@KungFuKirby : How did you end up having edianness problems with BRRTools ? Did you recompile it under a big endian system ?