No, no, no, bad, bad, bad.
Forcing people to play a certain way so blatantly like that is terrible game design. The way to promote job diversity is by, you know, actually promoting job diversity and making each job good, fun to play, unique, and special in their own way so that each job has something that appeals to different people according to their own personal playstyle, personality, and aesthetic.
Have it so that cooperation from different jobs and a diverse skill set actually increases your DPS, as opposed to spamming the same move from the same job over and over again.
See my thread here for details:
http://forum.square-enix.com/ffxiv/t...llChains2.0%29