Continuing what appears to have become a series on the minutiae of Termite Terrace staff turnovers:
One of the last big WB cartoon staff shifts before the 1953 shutdown was the swap of story men between the Freleng and McKimson units, around 1950. Freleng no longer wanted Tedd Pierce as his story man, and he got Warren Foster, McKimson's story man, to come over to his unit, with Pierce going to McKimson. (McKimson would work with Foster on a few more cartoons after that, and Freleng bought one more story from Pierce, 1956's excellent "Two Crows From Tacos.") Foster undoubtedly wanted to switch; for one thing, if the studio had gotten downsized again, McKimson's unit would have been the next one to go.
It's often noted that the switch hurt McKimson's unit; though Pierce was the story man on one of his best cartoons, "Hillbilly Hare," he was described by Lloyd Turner as "the least creative" of the studio's three main writers, and while he was good at story structure and pop-culture parodies, he was fairly weak as a gagman and had "personal problems" (i.e. he drank a lot). McKimson, like Art Davis and unlike the veteran directors, wasn't particularly good at coming up with gags on his own and wasn't a great motivator; he needed Foster, a brilliant gag writer and a hard worker. Pierce brought out McKimson's worst qualities, McKimson couldn't motivate Pierce the way Chuck Jones could, and it led to a lot of cartoons with stale gags.
But I've always thought that Warren Foster was not a great fit for the Freleng unit either, because they also seemed to bring out each other's weakest qualities. Foster was, as I said, a superb gag writer; he always knew exactly how to write a gag for maximum impact, including his great ear for what a character should say after the gag. (I just watched the Freleng/Foster cartoon "Catty Cornered," and after Sylvester slipped on a banana peel, I felt somehow that the gag would not be complete unless Sylvester said something. And sure enough, he turned to the audience and said: "I s-s-slipped." Perfect.) But his stories seemed to lean a bit more toward... I wouldn't say kids' stuff, because his stories aren't kids' stuff, but his writing is a little more simple and less "post-modern" than Tedd Pierce's or Mike Maltese's. Maltese always tried to put some weird angle on everything, whether it was a gag or a line of dialogue. Pierce also had a writing style that was a little offbeat, at least for cartoons. Foster's writing tends to be more on-the-nose and direct. (I say "tends to be," I know there are plenty of exceptions.) When he took up the greedy angry Daffy that Maltese had created for Jones, he didn't give Daffy off-the-wall self-justifying lines the way Maltese did; he just had him say directly that he's evil, greedy and hates Bugs ("If a long-eared rabbit can be a star, so can a duck!"). And many of his stories, with oddball exceptions like "Rebel Rabbit," tended toward the traditional cartoon subjects: storks, fairy tales, gangster-movie parodies, and a strange obsession with putting Daffy in various suburban houses. He was a great writer, just a little more of a straightforward cartoon gag writer whereas Pierce and Maltese and Bill Scott were a little weirder.
Foster's best work was done with directors whose cartoons were a little anarchic: Clampett, Tashlin, and the early McKimson. He brought his great grasp of gag writing to their cartoons, and they kept his stories from becoming just a succession of traditional gags. But Freleng was the most traditionalist of all the WB cartoon directors and the one whose cartoons had the most tendency to become a succession of mechanical gags. (Yes, even after Chuck Jones was making two Road Runner cartoons a year, Freleng was making more spot-gag cartoons than Jones would.) He teamed for the first time with Foster, a writer whose main strength was the old-school cartoon gag, and at first, it worked fine: most of their first cartoons together, released in 1951, are very good, and some, like "Putty Tat Trouble," are terrific. But as their collaboration went on, more and more of their cartoons together became a sequence of undifferentiated gags, distinguished only by the setting and maybe some relevance to the subject. By the mid-'50s, most of the Bugs/Sam cartoons are just Sam trying and failing to catch Bugs, and most of the Tweety/Sylvester cartoons are the same exact gag with Sylvester.
Pierce was probably not anybody's first choice as a story man: presumably Freleng got him because after Pierce and Maltese stopped working as a team, Maltese decided to go with Jones full-time. But some of his cartoons with Freleng in 1949-50 are a little more interesting than what Freleng would do with Foster with the same characters. The Bugs-Sam cartoons, in particular, are a lot better with Pierce writing them, because they have more of a story/structure spine under the gags (even if it's only a little structural thing like the ship sinking over and over in "Mutiny On the Bunny") and Bugs and Sam's relationship has more of an edge to it -- Sam's the antagonist, but we sort of feel bad for him for the way Bugs abuses him --- unlike in the Freleng/Foster cartoons where Sam would be more of a traditional cartoon villain. "High Diving Hare" is the perfect meeting of Freleng and Pierce's talents. It's clearly a Pierce story because, as Freleng often pointed out, it has only one gag, and that's often the way Pierce wrote. ("Rabbit's Kin," for McKimson, is really just a series of variations on the "lumps" gag.) But the variations on a single gag are more interesting than a series of vaguely different gags would be, and Freleng's talents for gags and timing keep us laughing harder at every variation. Freleng did his best work with Maltese, or with the Pierce/Maltese team, but I think Pierce was his second-best writer; with Foster, his cartoons got awfully bland and childlike -- and that's not a slam on Foster or on Freleng, just that they both seemed to work best with someone else who could push them in more offbeat directions.