I replayed the series recently and I think the gameplay didn't age that well especially after you played some japanese puzzle games like Professor Layton or Ace Attorney. It's not the difficulty of the puzzles but rather there is almost nothing intuitive about them and a lot of times they are detached from the story. The story, the writing, the humor, and the characters holds up of course but not the gameplay.

I love both game series, but Ace Attorney has multiple moments where you lose by presenting evidence too early or the "wrong" piece of evidence (even though it would also prove your case). The later games are better but even the Great Ace Attorney has instances of this.

Professor Layton almost all the way through includes trick puzzles which have non obvious answers as well.

Obviously the games aren't perfectly obvious and later games are much better, but they are generally much more obvious than something like King's Quest which was properly brutal. I remember needing occasional hints to manage monkey island but nothing like completing King's Quest where I had to constantly check the walkthrough.

I think this is a problem of many of those old click to play adventures.

For instance, I found Leisure Suit Larry I in many ways better, from the gameplay, than "Leisure Suit Larry: Love for Sail!". Now, the latter made much more use of the mouse, so it was easier and simpler for most players; but I found LSL 1 just so convenient and quite fast to play, if you could handle the keyboard well. It was of course nowhere near as convenient as clickety-click via the mouse, but I had that impression several times with games. SimCity 1 was IMO much nicer to play than later simcities; same impression I had with civilization, the actual gameplay got progressively more annoying, slower and laggier.