Well then its not a good solution from Microsoft
I would say it's not a good solution *for you* and your needs. With regards to your phone's camera roll, OneDrive is intended as a cloud backup/storage/archive. For better or worse, it is not meant to simply mirror the contents of your phone. OneDrive has the advantage of infinite storage space. I suppose they could have a separate "Archive" folder that would store every photo, and separate "Camera Roll" photo that synced with your device (and vice versa, so that if you added/deleted photos from the web they would be pushed down to the Camera Roll on your phone).
Perhaps the limited phone storage makes it impractical to have a two-way sync relationship, so instead the default flow is in one direction from the phone to the cloud (with the ability to manually pull information out of the cloud).
So, what should you do? Consider "managing" photos just in OneDrive. Periodically go through the OneDrive Camera Roll and move or copy photos you want to keep into a dedicated folder or set of folders. You can either clear out the Camera Roll folder or keep it as an archive. You can then copy that folder of nice photos from OneDrive and put it on your phone.
Consider giving up "management" on your device. If you use OneDrive as described above, then you just need to periodically purge your phone's camera roll to ensure you have space. Don't bother picking and choosing stuff. Do all that online.
The mistake you're making is trying to manage this stuff twice. My hope is that Windows 10 will intelligently allow selective folder sync (offline access) on phones the way it does on tablets. This way your folder of "keepers" could just be available offline on every device, without needing to manually push or pull things.