I always liked Diane Duane's books. I absolutely loved The Wounded Sky, which this episode is based on, although it's so heavily altered that only the original concept is left. But that's just as well, as it avoids the messy "this happened to the same characters twice" that Doctor Who has run into by adapting Jubilee, Human Nature, etc. And the special effects weren't ready for a character like K't'lk back in 1987, anyway. ;) Still, this episode successfully captures the spirit of the book, especially in the "realm of thought" that the Enterprise finds iteself in, and in the character of the Traveller.
I find myself being more sympathetic to Wesley being a kid genius rewatching this, especially Picard's taking the Traveller's advice to guide him. At the time, it just felt like "Oh no, they're letting the kid on the bridge permanently," but in hindsight, knowing he'll become another Traveller and this is a necessary step for him to grow in that direction, it feels like it works. (Although Wesley's awestruck behavior at being allowed on the bridge is still cringe-worthy. The poor kid just wasn't allowed to be cool until the second or third seasons.)
And oh, the music in this episode! Not the bland, sanitized background bars that would become the norm later, but music that actually tried to capture the majesty of what we were seeing on screen, and make you feel connected to it by including the Next Gen theme in it. Fantastic.