Content Fragments are now used widely in AEM project majorly in headless and hybrid model.
But still there are some features that can be added in content fragment that can make it more valuable:
1) Use of Multifield. Currently the multifield works fine when there is one level of child but for some cases we require multlevel multi field that does not work fine as it works in the component level.
2) Live Copy Inheritance in Content Fragment is not supported.
3) Asset level versioning shows the version number , it should also show the date of version so this will help to track the exact revision as well.
4) Dialog level clientlibs instead of override dam.cq one for dialog level events.