While I do concede your point about the world themes being cooler in SMB3. I also like the graphics and look better in SMB3, but the game mechanics in SMW were way better and you could do some crazy stuff. The stupid shit you could pull off with the cape was really fun. The Underwater worlds were actually good. The Ghost Houses and Ghost Ships were interesting and I liked the as a replacement to the Fortresses in SMB3. The Star World and even better The Special Zone were really unique and actually pretty challenging. There was just so much more in SMW in the way of side areas.
I'll also give SMB3 having better sidegames like the Slots and Card Matching for items. SMW should've kept the inventory could've been interesting.
Yeah SMW is a much more mechanically rich game, not even going to attempt to rebut that. At high-level play it is super fun to watch, at the end end of the day though in just the basic game the levels just aren't as fun to traverse.
It's not even just a matter of the overall theme as it is the structure. Mario 3 has a lot of levels that feature elements completely unique to themselves such as the pyramid in 2 or Kuribo's Shoe and the castle in 5. I feel overall out of the entire classic Mario entries 3 tries the most things.
Not that I think SMW is in any way a bad game. I called it a step back (which I do think it is in overall level design), but it's still a fun time.
The best thing, as you said, that SMW introduced was Star Road and Special World. Including harder bonus stages after completing the main game was a good choice for the franchise especially as the games grew easier over the years. The enemies wearing Mario masks upon completion is a fun touch as well.
I have to disagree on Ghosts Houses though, nice music, spooky atmosphere, absolutely aggravating for 8 year old me. My childhood grudge against them burns ever strong. Mazes with time limits were the bane of my existence.
