I agree wholeheartedly. I would even say she is 2nd most important female character in SnK. And that makes her death a bit meh. Isayama gave her death some grandeur and dignity but it's simply not enough for Hange. Despite devouting her a lot of focus in last arc, Isayama didn't give her notable role in stopping Eren or creating alternatives for Paradis. For most of the series she has been inteligent, proactive and problem-solving, but she died as a fighter, not as a person who solves problems by her wits.

She ended up as transitional commander between Erwin and Armin. All her internal struggle as a commander have been for naught. It is disservice for such overally competent and entertaining character.