As someone mentioned, Nextcloud (or other similar products) is used also as a backup tool. And in that case, current structure is better. I know many cloud solutions are offering or swithing to this type of file sync and usage, but it is really, really important give user all possible options and he should decide what to use. You can put Virtual drive as default setting, but don’t remove what we have now.
I will put Nextcloud client on autostart, so it’ll always be on. So in that case, virtual drive is no better. I agree it is usefull, and all the services I used or use (Seafile, pCloud, Tresorit, Onedrive) have something similar. But also have standard sync option. If Nexcloud ditches current client, it might not be as competitive as it is now.
So please keep both options on the table. If it works (and at this moment it’s working great for me), don’t fix it 
I’m not sure what else need to be improved in desktop clients exept maybe e2ee workflow. So keep fixing exisiting bugs and let the code live 