Been playin' the Paper Mario games I haven't played. I stopped interacting with the series at Super Paper Mario on the Wii.
While I think—in some respects—the games after The Thousand Year Door have weaker gameplay loops, Sticker Star has poison the well when it comes to discussin' the series beyond TTYD. Currently going through Sticker Star n' the worst I can say about it is it's tedious at times. I'll save my full thoughts for when I do my media thread post on it, (got a few already in the back burner...) but I don't get the vitriol this game gets at times.
Lastly, I will die on the hill that the series' music has gotten progressively better with each new installment. Like Origami's just.... primo... god-like stuff.