Some of Monty Python's routines are absolute classics that merit repetition, because they're that good. But that's only the very cream of the crop. Most skits were eminently forgettable; a fair number were just plain bad. And watching Flying Circus, it often seems as if they had no idea which were which.
Monty Python was willing to go way outside the box. The box usually exists for a reason: it's the material that has worked. There are some brilliant new ideas outside the box, and a vast world of crap. It takes a genius to find the pearls among that crap, and Monty Python were without doubt just such geniuses. But even so, what they brought back still required a fair bit of sifting.
Flying Circus episodes can be enjoyed simply for the joy of the search. The skits that fail were (frequently, at least) noble failures. They came, they tried, and we mostly forgot about them. If their stunning, world-changing successes did nothing more than expand the box... well, that's an accomplishment. You're never going to destroy the box entirely, because the fact is that the vast majority of ideas are just plain bad.
I'll be happy to see if those geniuses can find something worth expanding the box still further, but I have to suspect that it'll look more like Flying Circus than Holy Grail. (Holy Grail was, itself, a holy grail: a stunning fraction of it worked, in a way that few other things they tried did.) Good on them for trying it; it's the risk of failure that makes the successes worthwhile.