Well it depends on your definition of 'MMORPG'
The choice of language or framework or network library depends on the scale(concurren player number), responsiveness(real-time or turn-based or hybrid etc) and play-type(control via 'WASD' fps style or via click to move/attack command sytle) of 'MMORPG', so there is simply no 'best/optimal' choice of language or framework.
You need to make a basic idea on what kind of game you wanna make and the time you wising to spend on the different learning curve of different programming languages or exist framework/server library etc.
Just my 2 cents though. -_-