With some many missing features in JSM, why spend time to mess up and degrade navigation?! The new UI is so poor and confusing. The old UI was great! Please give us the option to choose which UI to use!
This has been discussed at some length here. A lot of users don't seem to care much about the change, probably based on how they use Jira/JSM. Some seem to like it, and others hate it. It's hard to know the breakdown. I'm not aware of any public user survey about this but Atlassian noted low opt-out rates during the EAP as evidence that users are happy with it.
After reading some of Atlassian's posts and some short discussions with them, I do not really understand why they think the new nav is better. These posts might give context for future readers:
Unfortunately most of these do not really directly say WHY Atlassian have made the change.
I posted earlier to express my feelings on the matter.
I know it is backwards to introduce dramatic changes to the UI in one big bang release then make incremental improvements after the fact but Atlassian has at least announced that we can resequence our Starred items in the sidebar now: https://community.atlassian.com/forums/Jira-articles/You-can-now-reorder-the-starred-projects-in-your-sidebar/ba-p/3075508
I was really disappointed at the new UI myself but after a few weeks the irritation faded even if some common tasks are still less efficient than before. Change is hard but there were apparently technical reasons that they cannot support the old and new UI concurrently, hopefully the benefits of the new architecture will outweigh the pain while they sort out some of the more painful aspects.
I was fortunate enough to spend a full hour with an Atlassian providing my feedback on the new UI and I have some hope since the article I linked above was one of the items I mentioned. Obviously it would be better if they gathered feedback from a wider cross-section of customers before rolling out large UI changes but I accept incremental fixes after the fact as that's better than switching to another product for me.
As an Admin, I am far from thrilled about the new UI. And I totally agree with the above statement.
And it is clear that Atlassian is not listening. There is a lack of concern about users feedback. It seems Atlassian is dead set on moving forward with their direction. They do not understand how we use it in fast-paced technology environments. (It seem they think it is good for 'personal'. The UI is very inefficient and I don't see any Atlassian concern for user comments.