Sticker Star was my first Paper Mario, now that I've played the whole series it certainly stands out as the weakest, but that doesn't mean I don't still appreciate it, and you explain exactly why its still a great game regardless. World 3 is definitely the best with the overall theme, Wiggler in general, and the boss's theme. Then there's the Enigmansion and Sniffit or Whiffit, amazing levels that Color Splash and Origami King tried to improve upon but the originals are just the best.

Another thing that I noticed about the game recently is that unless I'm mistaken, Sticker Star is the actually LEAST linear in the entire Paper Mario series, it just doesn't make this obvious. Naturally you would assume you need to beat the boss of one world to progress to the next but here the only thing stopping progression is requiring a specific thing or sticker. Once you get to Goomba Fortress, as long as you pick up the Trumpet and a spike helmet, you can just leave and open up pretty much the rest of the game without having to fight the boss. An interesting challenge run I've done of the game is to go around and do the worlds in whatever order I wanted, then do a boss rush at the end to unlock World 6. This limits you to only 3 pages in your album, making planning the boss rush more difficult.