I actually liked the cryo tube. Yes, it was a test your inversion settings trick (if you look the wrong way does Cortana complain or anything? I've never tried that) but I thought it was a subtle one that was well integrated with what was happening.

: -the elevator climb. Replace with cutscene on higher difficulties

Yeah. It was unnecessary to have me push a direction with a huge margin of error all to avoid some silly pieces of debris. I do like the first person view part when the vacuum and debris knocks you into the elevator though. That felt immersive.

: -the Elite at the top of the elevator shaft. On higher difficulties, he'd be
: a normal foe, and you can retrieve his sword

Yep. Press X to twist Elite was very silly. Bungie showed that even standardish enemies can be very interesting, like that Brute Chieftan at the end of the Ark level in Halo 3. His custom animations in wanting a one on one battle and his pack's standing on the sidelines while the battle occurs is pretty neat. The Elite at the top of the elevator could have the same sort of novel custom actions applied to him to make him a fun and unique initial challenge.

: -the boarding Phantoms. One wave isn't enough, on higher difficulties, I'd
: make it a longer fight. At least 3 sets of enemies from each Phantom. Or
: it'd be just one wave, but it would introduce Jackals

Agreed. Perhaps not so much in having more enemies come out of the same phantoms, so as not to make them hold more than they should, but having additional phantoms attach would have been neat. Bonus points if they had one attach to the main front window that you just opened.