As I've explained before, I've found the whole "these are new breeds/species/subspecies" thing to be completely and utterly lacking. Whether it's the radically different skull structures of the "Ibie'sh Jackal" or the radically different integument of the Halo 4 Grunt (which wasn't even given the "it's a new subspecies" excuse), these cannot possibly be members of the same species, or even of the same genus or family, and at best are part of the same order. In fact, the Bungie-era Grunts are likely not even in the same taxonomic class as the Halo 4 Grunts, as the former have chitinous exoskeletons and the latter have a leathery, scute-covered hides reminiscent of tortoises and crocodilians, and we don't see such radical differences in integument at the class level. Nobody with a basic understanding of evolution and comparative anatomy can seriously believe that the Halo 4 incarnations of Grunts and Jackals are the same species. It doesn't just break willing suspension of disbelief: it stomps a mudhole in it and walks it dry. I could buy the very avian Skirmishers as maybe being a semi-distant evolutionary cousin to regular Jackals, much like gorillas are to humans (but closer in intelligence), but there's no way in hell I can buy the new Jackals and Grunts as being anything even remotely close to the same species.

This has been my biggest non-gameplay annoyance regarding 343i's handling of the Halo franchise. As I've gone over multiple times, the extreme lack of visual congruence between Bungie-era Halo and 343i-era Halo is immersion-breaking, serving to pull me out of the fiction. It makes it feel like I'm not even playing in the same universe. In Halo 4 when I look at the Chief, I don’t see the same suit of Mark VI, even though it’s supposed to be the same suit of armor. When I look at the Dawn, I don’t see the same ship, even though it’s supposed to be the same ship. When I see Grunts and Jackals, I don’t see the same species I fought in previous games. There's never been any established precedent in the fiction for natural evolution (or even genetic engineering) working significantly different from how it does in real life. There's no precedent establishing that nanomachines can completely reconfigure an entire suit of armor in cryo to look like something completely different. And there's never going to be a satisfactory explanation for why the remains of the Dawn suddenly changed into a ship class that didn't even exist during the events of Halo 3, or how it suddenly grew to be the size of the Infinity.

The Dawn pretty much exposes all the other reasonings (when we got them) as a bunch of hooey designed to placate the fans, and that 343i's art department by and large just didn't care. Not about consistency, not about respecting what came before, not about plausibility. Bungie could be bad about this at times, but redesigns were rarely as radical and far-reaching as anything 343i did, and they usually had plausible explanations and at least usually looked similar to what came before (the biggest inconsistency on Bungie's part was Brute design). But 343i elevated redesigning things to an art form (pun semi-intentional). They've been far more extensive and radical in that regard. If they just came right out and said "We're redesigning a lot of things, radically so in some cases. We don't have any real reason besides 'We want to.' Deal with it," I'd probably be more accepting. I'd still be disappointed, but at least there wouldn't be BS excuses that complicate everything to content with as well.

Of course, I'm getting to the point where I personally don't regard 343i-era Halo as actual canonical events in the Halo-verse, but rather as a dream the Chief is having in cryo. It's the only thing that makes sense anymore.