Fair point. And Super Princess Peach too. Mostly because I couldn't quickly find or procure a shot from them of Mario shooting a fireball in front of a pyramid, and also if I'd included SM3DL I would've had to include the Galaxies too, and the point would've gotten muddled.
I still think it's a fairly fair comparison, though. It's the progression of the Super Mario Bros. series. SML1 and 2 and YI were part of the SMB series at the time, though in retrospect we consider them their own serieses. They tried dramatically different visual styles from game to game. Look at SMAS, where instead of just porting it all to SMW graphics, they kept the unique style of each game (except for the subtle differences between SMB and TLL, which were glossed over). And just when it looked like they might settle on the SMW style after it was used in SML2 (and Mario Paint, and various other SNES games), Miyamoto said screw it and made YI (in protest against being pressured to make it look like DKC... which would have looked quite a bit like NSMB).
The graphical style of the current games considered part of the core SMB series has not changed at all. NSMBW, NSMB2 and NSMBM are just higher-res versions of the same graphics of the same worlds of NSMB seven years ago. And whereas YI back then was an out-of-nowhere massive graphical shakeup, YIDS's graphical style was a safe, sanitized copy of YI. And in that sense, there hasn't been any equivalent of YI, or PM for that matter. No stylistic surprises. Everything is safe.