Overrated...and not enough Lucy!
While it was nice several years back when they dusted this one off and started showing it again, A Charlie Brown Thanksgiving is just nowhere in the ballpark of the classic 2 Peanuts specials (Christmas and Great Pumpkin). It's warm, amiable, has the great Guaraldi sound (and a whole original song) but little else. Certainly it doesn't have enough Lucy whose appearance may qualify as the first cartoon cameo ever.
Linus soldiers on gamely and tries to give a Thanksgiving themed "big speech" near the end, just as he did in the Christmas one, but perhaps the simple problem is that Miles Standish really doesn't hold a candle to God. It's also curious that he rides away with Chuck and the gang at the end. Isn't he expected home for dinner? Is he making a statement that Lucy really IS that annoying to be around?
From the classic Peanuts era there are better options that were done (including the now never seen Motocross special). Still, it gives the warm fuzzies, and remains better than almost anything done in this genre today.