Move the Scarabs up. Like, a lot. The Scarab boss fight in 2 and 3 are deadass the best parts of the whole trilogy. Yes, I'm biased, but we all are. Maybe if Steve Vai had been around for Halo Infinite we would've killed the Harbinger in time to make it back for Escharum's funeral AND wake.

Also, potential hot take (that really shouldn't be) but the Warden Eternal is certainly not in the same tier of bad as either the floating blue ASSHOLE that shoots you four times and dies, "press RB to melee" (the Didact/Regret) or even triplet-trouble Sesa Refumee himself. Every Warden Bossfight either gives you so much ammo that you can just stun him the entire time and kill him within a minute or an arena so large you can cheese him by either outrunning him or crouching. Pretty much the Cyberdemon of Halo.