MTP is fine for transfering files. Sadly it is not quite as fine for tasks such as creating incremental backups. Windows doesn't map MTP devices to a drive letter, hence not all software supports MTP devices.
Alternative solutions that would allow mapping to a drive don't work well either. An FTP server installed on the Android phone cannot be mounted permanently, as the IP address willl change on your typical wifi. An SMB server will not work on unrootet phones, because the port for SMB is hardcoded in Windows and Android needs root permissions to create a server on that port and I have yet to see a method that would work with a cable.
So while I perfectly understand the reasoning for switching to MTP, especially for devices without SD-card slot, the switch does create its own set of problems.
That said, once having accustomed myself to the new situation I haven't actually missed Usb Mass Storage.