Michael,
I maintain and sell an application that allows FTP access to the MII virtual file system. Most modern IDE have the ability to integrate via FTP. Its free to try and I would value any feedback you could share if you try it. If you would like more info please contact me via the email address on my scn bio.
With UI5 gaining a lot of momentum I do think going forward you will see more movement towards that development infrastructure for front end work.
I haven't seen a roadmap from sap regarding the future of MII development tools in a long time. I imagine the SSCE could be further enhanced over time to allow more functionality. Salvatore Castro , maybe you can shed some lite on the subject?
Regards,
Christian