u/SpongeGuy11

Looking back at season 6, it does feel pretty different from the rest of the revival era of the show.

With these things I'd mention:

• Mr. Crocker and Timmy's dad don't get shoehorned in every episode, with Crocker especially only really being the main villain in Cheese and Crockers, involved in team ups in For Emergencies Only, Dread and Breakfast, and Wishology, and only a supporting role in other appearences (usually in his crazy teacher role), not too far from how often seasons 4-5 use him.
• Vicky's still a relevant villain at this point, being in main antagonist roles in Open Wide and Say Aaahh and Vicky Gets Fired, supporting role in Wishology, The End of the Universe-ity, Merry Wishmas, and King Chang, a robot likeness of her in Wishing Well, and minor ones in Odd Pirates, Dread and Breakfast, and Birthday Bashed, not far from how season 5 does with her. Probably the last season she was genuinely a consistently relevant character, only being in 2-3 episodes a season in seasons 7-10.
• The other non-Crocker school characters like Chester, AJ, Francis, Trixie, Tootie, Tad & Chad, Sanjay, and Elmer are still relevant at this point rather than being background fodder by the end of season 7. Same for the likes of Anti-Cosmo & Anti-Wanda and the Pixies still being there at this point. Also the last season for Mama Cosma, Chip Skylark, Brittney Brittney, and Adam West voicing Catman (Jeff Bennett takes over after this).
• Dark Laser's surprisingly at his most prominent this season, lumped with Vicky and Crocker as Timmy's biggest enemies this season (outside this season, he's only in two more individual episodes in seasons 7-8 and then exclusively with the LOSERS in season 10).
• Unlike later new characters, Poof doesn't take up that much attention with the "wish of the week" format still intact, with an argument that he occasionally blends a little too much into the background at times.
• Tried to still follow the continuity of seasons 1-5, even following up on some plot points such as the Mark Chang vs Mandie plot. Birthday Bashed is probably the closest continuity error this season with Crocker in the video being shown to have different fairies, but that might have been for the purpose of making the video.
• The "Cosmo and Wanda lose their wands" gag isn't as prominent as season 7 onward.

Does anyone think the different vibe season 6 has from the other post-original run seasons could stem from the different writers?

For context, the writing team for season 6 was Butch Hartman himself, Kevin Sullivan (there since season 5), and Scott Fellows (joined since season 3 and promoted to story editor with Steve Marmel and Jack Thomas gone for other projects). Season 7 lost Scott Fellows and brought in a new wave of writers like Ray DeLaurentis (who became story editor for the remainder of the show), Will Schriffin, Ed Valentine, and Joanna Lewis with season 9 adding more like Kristine Songco, Kevin Arrieta, Sindy Spackman, Alec Schwimmer, Ellen Byron & Lissa Kapstrom, and Becky Wangberg, with only Butch Hartman (though he stopped writing after season 8) and Kevin Sullivan from the original run remaining (Dave Thomas briefly returned to writing one more time in season 8 though).

Season 6 in a sense having more of the original run writers and a different story editor than the rest of the revival era probably contributes to why it feels closer to seasons 1-5 than to seasons 7-10.