THE REVENANT is a good movie, but not a "great" story. Not like BIRDMAN or CHILDREN OF MEN as far as the character's development over a very difficult journey. For Hugh Glass, it really seemed his challenges were much more of the physical rather than dramatic variety. He never really finds himself in the same position as Fitzgerald throughout his journey so it felt like they missed an opportunity to really go the full distance spiritually though they reach for it.
For me Tom Hardy - despite getting a lot of criticism from some reviewers for being two one dimensionally evil - delivered the most challenging and dramatic performance. Certainly, his greedy, brutal and bigoted nature at the outset seemed offputting, but I found him very compelling as he faced and made choices that were still physically demanding - though not as much as Glass - but also very morally conflicted.
Also, the movie did suffer a bit from being unclear exactly how injured or healed Glass was at any particular moment. Just as in scenes where a single-shot flintlock would fire two or three shots even though Glass has no time to reload, his mobility and level of injury/exposure varied based on what the story demanded in any particular scene.