Depends what you count as 'homebrew'. PCE/TG16 have a handful of a little/tiny games for it. Public stuff too. Some of the stuff B_T listed for the Genesis, is too small to really can't as homebrew games IMO. But that's just me, because technically they are 'games'. And not just something unfinished/uncompleted.
Nando: Que paso. Que un juengo homebrew por snes, no es bueno. IMO, anyway. It's some German game. I forget, but it was released on cart and did have 4 simultaneous players IIRC.
Yeah, snes isn't as clean an architecture as say the PCE/TG16 (video side), or more so - the Gen/MD (video/main cpu side). But that's kind of irrelevant. Once you learn a system, you know the system. You get used to all the quirks and convoluted-ness. The c64 is pretty convoluted, for what they do with it now (and since the past 15 years). They have to write some really complex code/structure to do a lot of the stuff - compared to when it was first released. Same with the Atari 8bit small computer line (even the 7800). And yet those systems are currently getting development love (though atari systems seem to be on the rise will the c64 is on the decline, for new games). Having looked over all the registers and what it takes to do the stuff they are doing nowadays, on those systems, I would say the SNES is less complicated than either of those system.
I think a good example (IMO) is the PCE with HuC. HuC needs a decent amount of support to get some speed back out of it. That makes it more complex, than say just a simple ASM environment. And yet, look at what Old Rover and Arkhan are doing with it.