I originally didn't see Mark Mayerson's post from last year on the Walt Kelly/Chuck Jones "Pogo Special Birthday Special" from 1969. Fortunately the special still seems to be available on YouTube. Unfortunately, it's not a whole lot better than I remembered it being.
I saw the Pogo special when I was quite young, before I had ever read a Pogo strip. It was available on VHS at the time, and my Dad, a big fan of the strip, saw it in a video store and advised me to rent it to get acquainted with Pogo. But the special was so dull that I couldn't get through it, and it probably turned me off from seeking out the strip (though I eventually did, and it was great).
Kelly blamed the failure of the special on Jones, telling his ex-Disney colleague Ward Kimball that "the son-of-a-bitch changed it after our last meeting!" I don't fully buy this. Jones certainly made some mistakes that Kelly did not approve or approve of, particularly giving Mam'zelle Hepzibah the Skunk a new, human face. (Why he would do that when he'd already spent years successfully drawing a skunk -- who probably influenced the character of Mam'zelle Hepzibah in the first place -- is beyond me.) But Kelly wrote the script and did some of the voices, and it doesn't seem to me that he's blameless for the weaknesses of the film; the lines the characters are saying are less funny than a typical week of Pogo strips, even circa 1969 when the strip was not as great as it had once been (but still funny).
Jones and Kelly undoubtedly were hoping that The Pogo Special Birthday Special would do for Pogo what another half-hour prime-time special had done for Peanuts. But A Charlie Brown Christmas preserved the tone of the strip, in part by lifting large chunks of dialogue directly from the daily strips. The Pogo special doesn't feel the same as the strip, not even the Sunday strips where Kelly deliberately toned down the political content. (Kelly saw the Sunday page as essentially a separate strip with a separate, younger audience than the weekday strips.) Some of that is Kelly's writing, and some of it is Jones' slow pacing.
There's a pacing problem built into any adaptation of Pogo, which is that the pacing of the strip doesn't match the setting. The Pogo strip moved pretty fast, even in the strips where Pogo and the gang were just lazing around the swamp. It moved fast because the panels were crammed full of dialogue and there was always some piece of background action to keep your attention. Translate that to animation and you've just got cute animal characters lazing around a swamp, and it instantly feels too slow and soft for Pogo. That's one problem Jones didn't solve. But he compounded it with the pacing issues that plague all his work from the early '60s on.
Watching it, I tried to figure out why Jones's later stuff feels so slow. There are a bunch of contributing factors, like the musical score (when it was up to him to dictate what kind of music he got, he tended to favor scores that didn't really push the action along) and the tendency to linger on his favorite poses, but what strikes me most is that these late Jones cartoons have a "show-offy" feel as regards their full animation -- that is, there's a lot of time taken on in-betweens and fluid movement, too much time taken between funny poses. (Remember what Michael Lah said about animating for Tex Avery, that the'd always find themselves taking out in-betweens because they found that the pose reels had sharper timing.) At some point he seemed to lose track of what all great comedy animation directors know, that if the animation is too full, you lose the timing. I don't know if that was related to his admirable determination to continue with full animation at a time nobody else was; but it does seem like his later stuff has a tendency to call attention to the full animation, whereas when full animation was taken for granted, he was more willing to pop characters from pose to pose in a funny, snappy way.