The system should be designed with much heavier use of cache on all levels.

Some examples of poor design in Jira that your dev team should attend to:

• Trying to edit a comment, there's no reason for an Ajax request to load the dialog. The text is in the page and so are the edit tools. Only ajax request should be on updating it.
• Trying to change assignee on an issue would load the users list via Ajax request. Why not cache this in localstorage?

There are many more occasions where needless requests are made and the system thus responds much slower than needed. Perhaps it becomes more evident on the cloud service which is obviously overloaded. I could now see that refresh a simple issue page would take 1.1-2.5 seconds to fetch the HTML part of the page (without resources). This should have constantly been under 1sec and the changes clarify the server is overloaded.