I don't like most if not all his characters. Well I actually like Locus but only like Felix pre-reveal he's a villain. I'll elaborate on that later.
But basically... Grey is annoying to me.
I only liked Kimball before S13 bc in S13 so much of her character just feels like an opposition to Doyle.
I never rly liked Doyle and I dont like the voice acting for him (that ones just me).
The Lieutenants I also only liked in S12 because in S13 the show gives off vibes it's trying too hard to make them endearing as characters analogous to the Reds and Blues in the blood gulch era without the history and context that justify having earned that endearment.
All in all, his OCs don't feel as authentically appealing as he makes them out to be imo. And this wouldn't be a problem for me if he didn't give them SO MUCH focus. They're everywhere when I rly JUST want to see the Reds and Blues.
I get the whole conceit of his villain is a Deadpool-style, snarky, self-aware, asshole mercenary. But that snarky part of his personality only feels good as him being a good guy because after those traits dissolve in the EVEN more typical 'monologuing and evil laugh' type villain which is arguably even more cliche than the trope they try to subvert with him as the "rough mercenary with a heart of gold" (paraphrasing here).
He's just not as interesting as a villain to me and I LOVED his character pre-twist but afterwards the true nature of his character seems even less compelling than the persona he masks as for the New Republic. I would've loved to see the good version of him continue, as it even seems like he's building a relationship with Tucker (that is meant to be deceptive ik but if given a genuine arc could've been interesting to me)
The alien mythology they do include before S13 is minimal and seen through the lens of the Reds and Blues. And because RVB exists alongside the main Halo universe you get the idea the Covenant and main series continuity exist elsewhere and the Reds and Blues were just in a small part of THAT universe.
And the idea of multiple swords and the temples I like but exploring that mythology feels like it shouldve been it's own season or arc?? Like I said this season is juggling too much and so the temples are almost sidelined in its own story as it just serves as a plot device to raise the stakes when it's not given much preemptive besides Tucker's own sword, which is supposed to have an origin as just part of Gamma's plan to deceive Alpha.
What was written to be a parody of Halo's own worldbuilding is given serious context, and I suppose you could argue that embodies the nature of the series (parody given serious context) and it does, but they don't do enough with it and it just so comes out of nowhere that I can't be bothered to care.