While not a point and click, Psychonauts is widely considered to be a worthy successor of the golden age Lucasarts craziness. Let's have a look at the synopsys: a runaway circus boy goes to a summer camp for psychics lead by a international team of superspy. He discovers that a mad dentist is stealing everyone's brain by making them sneeze, and in order to get him he has to travel into the mind of several deranged persons. Certainly on par with the purple tentacle trying to take over the world or the deathly travel agent, if you ask me :) .

Also, while not being a point-and-click game stricto sensu, you should really have a try at Stacking. It maybe not as brilliantly written as Psychonauts, it has some pacing issue but it's a really charming adventure (with Matryoshka dolls !) from the start to the end !

I would not consider Psychonauts a worthy successor, nor do a wide section of people who have tried it. A good deal of the issue seems to be exactly because it's not a point and click - it's actually a 3D platformer with a number of playability issues. Most point-and-clicks have major playability shortcomings as well, but they're such different breeds that the appreciative audiences are distinctly different.

I never liked Psychonauts. The humour was spot on, but it wasn't an adventure game at heart; it was basically a bunch of mini action games strung together where you run around in people's minds, and those mini games were awful. Really cheap-looking 3D, stupid goals (collect dream symbols and stuff), and just overall annoying.