Do I need to reoptimize after JUST RENAMING MTPs?
If yes, will reoptimization last long?
I just run a small test and it seems that if you rename one mtp and you regenerate the quality report, the name does not change.
BUT if you reoptimize it does change. Maybe it is safer to reoptimize…
I hope it takes less time than re processing
The Reoptimization will not change the quality of your project if you just Rename a MTP.
As Oliver said, you should Reoptimize if you want the new quality report to have the correct name for the MTP.
Another case that the Reoptimization is needed is when Merging:
When you want to merge 2 individual projects that have common MTPs with the same name, then the name needs to be correct and updated. So, before merging, you should Reoptimize.