YouTube's Enhancements feature is still in the Video Manager, so users can still edit videos a bit before uploading, such as blurring, adding filters, and cutting videos. But if you need more complicated operations, you will need video editing software.
The fact that YouTube removes video editing on the site may bring some new features, because they no longer have to spend a lot of time on a little-user tool.
This decision of YouTube also makes us worry about the fate of YouTube's Capture application, which has been updated since 2013 but the number of users is still quite good. This is one of the remains of the 32-bit era and will probably disappear when iOS 11 is released later this year, around September.