I liked it a lot, but I think I like it more than most just because of the way I played it. Also, because I really did get lucky with having the right stickers at the right time.
I would have enjoyed this game so much more if my experience was like yours. Unfortunately it hasn't been.
Here's another tirade. Just some thoughts I've been mulling since yesterday.
When there's a communication breakdown between the designers and the player you might sometimes chalk that up to user error on the part of the player. With Sticker Star, however, those breakdowns happen so often that the blame absolutely must lie with the designers. The most egregious problem that Sticker Star has is that the puzzles are quite frankly crap, but that is further compounded by the fact that the game does a terrible job of imparting to the player the 'logic' of each sticker (particularly in relation to boss battles) and the fact that if the player has not yet found the sticker that is required to proceed then they will have to laboriously search through all the previous levels in the hope that they'll stumble across it.
Just to give you an example, I ran straight past the Light Bulb 'Thing' in the Yoshi Sphinx. I flat out did not notice it and ran up the steps to the next area. So when I finally hit a brick wall later on in the game and had no where else to explore except the darkened warehouse in the harbor, I spent hours just wandering about looking for the correct sticker.
I ended up wasting a Spotlight sticker, a Car Battery sticker, a Lighter sticker, a Matches sticker. When I finally got around to searching the desert again and found the Light Bulb I felt really dumb. Then I thought about it some more and realised that while I had clearly messed up and had made a mistake, the game had taken no account of me as a player. At no point had the designers thought, 'Hey, what if someone did not find this one very specific item?'. Each time I brought up 'Kersti' to get a tip all she told me was that I should go to the harbor, but without the item I needed there was no bloody point in going to the harbor!
I'm probably flogging a dead horse here, but I really do think that the Paper Mario series has gradually shed pretty much everything I liked about it. What I loved about those first two games was the hilarious characters, the setting (the Mushroom Kingdom but not as we knew it), the great art style, and the satisfying RPG elements. In my opinion the only thing that has been retained right through to Sticker Star is the great art style and music. Everything else has been shorn along the way.