Of course you need to do a QA on your own translation. But again: it is YOU who changes the status of the segment. A modified segment has the status draft (or translation rejected or sign-off rejected) and that is a sign, something was wrong with it. This is work in progress. Before delivery you will usually accept all segments in either translation, review or sign-off process. Then your file will also have the right status. But during work in progress the status must be kept as it is.

Please don't take me wrong, but this is what makes TS so unique. You can follow all steps done and if you are being audited, this is also a way to show the auditor, if the file has really been revised.

I support that suggestion. This is annoying, since after completing a translation, we usually have to self revise it or to do some QA, and the project is not yet "In review", from the translator's stand point.

This is not Trados Studio, it is the user. If you change the status of just one segment to translation rejected or translation approved, Trados will treat the file then as being revised. This is a feature and should NOT be changed at all. You have trhee processes in TS: translation, revision and sign-off. Properly used these are great for keeping track of what has happened with file(s) in project. In your case simply make sure all segments have the same status, i.e. translated, translation approved or signed off. But there are a lot of situations, where you need to keep some segments in not translated status—and in such cases the status of the file will of course show this.