This has to be one of the most stupid decisions ever? OF course it is a pain to wait for a period whilst you get a tank or healer, but this is just going to result in less tanks/healers at HM and Ops, thus they will then have to make those role-less too. If nobody is playing tanks/helas through the standard content you will end up with the following:
1) DPS queueing for Healer or Tank, and being as crap as the current people who do this.
2) People not learning any tanking skills, therefore tanks become rarer than they are now.
That will only happen if they make hardmode versions of this system. Storymode is supposed to be purely to experience the story. And it'll be nice for casuals to be able to queue for something quickly.
Personally, I'll do them once for the achievements. I already do tankless guild runs for the HM 55s; I have no desire to have content I can duo or solo.