Edge really needs end-to-end encryption for sync and better privacy policy

ragingrei I agree here very strongly.

Browser sync is about as sensitive as data can get, as it is likely to contain all kinds of personal information, ranging from political opinions to social security numbers* and similar. If there is no end-to-end encryption, all of these can be exposed by rogue employees, successful external attacks, or plain misconfigurations. So it isn't even about trusting Microsoft as a company, E2EE is simply essential for damage mitigation.

Given that end-users cannot be expected to be aware of these concepts, really only Firefox gets it right, but Chrome at least allows the end-user to make it so.

Additionally, Edge is the first browser I have seen to enable Sync by default, making the default settings even more important. 

* It isn't unlikely to see some websites transmit sensitive information through URI parameters, against all recommendations, so things like social security numbers can end up in the synchronized data like favorites. Other sensitive personal information is directly encoded in the bookmarks and, once sync for those is implemented, open tabs and history.