You have left the another platform which most people dont bothers. BlackBerry is almost dead.
Windows Mobile is the platform where you able to improve your productivity when comparing with the other. With smaller screen you cant do much. If you want your productivity to be improved you need a screen with minimum 14 inches. I dont care about less apps. But their innovations are the one which current generation top OEM needs to bring in.
Continuum which is microsoft latest innovation help me to improve the productivity on the go. I dont take laptop any more when i travel. I do take my phone alone. This doesnt means that it is replacing the laptop completely.
And microsoft is going to release a phone which will be able to run .exe files which will improve the productivity more.