If the SNES was the base definition of what the 4th generation is defined by, then I guess it would (PCE seeming middle generation). But wouldn't the Genesis be the basis for the 4th generation, at minimum? The SNES is pretty far ahead of the Genesis as well, in the graphical department. But even then, the SNES falls behind both, in some aspects.
There are some areas where the SNES falls short:
SNES and PCE both have 64k of vram, but PCE is actually much more flexible in its layout; tiles and sprites can be located and pointed to, freely anywhere in vram (included the tilemap area) - same with Genesis. Even the SAT (equiv OBJ table) can be located anywhere in vram (not exactly the same on Genesis, but still relocatable). The SNES has twice the sprite table size as the PCE, but the PCE is capable of showing all its sprite sizes per frame (16x16,16x32,16x64,32x16,32x32,32x64) - same with Genesis. The VDC in the PCE also allows writes to vram during active display. Even if the cpu ran 3 times as fast as it is (and even with graphics/vram data embedded as opcodes; ST1/ST2), it sill couldn't saturate the open slots during active display - let alone vblank. The PCE VDC also has the most flexible frame definition. You can define multiple frames inside a single NTSC frame, including multiple 'vblank' as game code would see it, as well resolution per scanline (three different dot clocks to chose, scaline length defines, etc). You can switch the display into 2bit pixel mode for either sprite or BG, on a scanline basis as well. It's extremely flexible. And PCE 32 subpalettes vs 16 on SNES.
The display of the PCE, is what I consider a true 4th generation setup. It does away with the hindrance of the 3rd generation quirks and limitations. All regs are buffered per scanline and can be written to safely without worrying about mid line update problems. Regs aren't shared, so updating them mid screen won't effect the video output. The ports are true 16bit (two separate address locations to the cpu; you don't write to the same port twice). It has a clean X/Y position update system per scanline (NES is convoluted for both X/Y, SMS has no Y updating at all) with buffered regs. You can turn sprites/BG layers on/off easily per 'VDC' scanline (you can have more than one VDC scanline displayed per NTSC scanline). It actually has a real h-sync interrupt system for doing full screen video effects. And you can even generate an hsync interrupts on every scanline, including the ones in vblank (which are whole lines). I've done this to drive a 15.7khz sample playback routine.
Minus the 2nd BG layer, the PCE and Megadrive are very close in capabilities IMO. Especially given the one year separation between the consoles.
Quote:
No native sample playback (no reverb).
The PCE? It has 6 DACs that are directly writable at any point, individually, and with mono volume as well as pan volume for each individual channel in this mode. The TIMER interrupt is specifically for this; sample playback as well note timing/tempo that isn't locked to vsync. Compared to the Genesis, which has 1 writable DAC and no volume control or any method of playing sample output other than brute force/timed code of the z80.
As far as the SNES display, I always considered it much closer to the 32bit generation. The rotation/scaling, transparency, huge master palette, number of BG layers, etc. The PCE and Megadrive are pretty close and set the definition of the 4th generation IMO. It's the snes that has the intergenerational aspects to it (although the weakest of the three processors, is a bit weird). A lot of SNES RPGs looks like PS1 2D RPGs to me.