Yep. No way is it ODST length if you actually slow down long enough to pay attention to the dialog and check out the environments a little. I wonder if people who complain about the length just rush through as fast as possible. It's not 343's job to satisfy players who treat the game like a timed arcade shooter (if that's what's really going on here).
I specifically didn't use sprint just so I could look around the environments in sections without enemies and I beat it in 6 hours and 23 minutes. I even backtracked in a few spots after I killed all the enemies just to see other routes I could have possibly used.
Nowhere did I rush the game.
Saying that game isn't short because you played it on legendary is kind of silly. Of course the game will be harder when played on the hardest difficulty. If someone plays the game on the difficulty that it's balanced around, though, you'll be in and out in no time whatsoever. CoD games have historically been seen as a short but they aren't if you play it on the hardest difficulty, too. I'm sure Halo 6 on easy could be a long game, too, if you spend most of the time looking for skulls and intel. If you just play the game normally, though, it's extremely short.