So maybe the following tweet from Ghostcrawler will cheer you up a bit:
@GersenKirth We would like to provide more 5-player dungeons than we were able to do for MoP.- Greg Street (@Ghostcrawler) August 25, 2013
Instead of five-man dungeons, Mists definitely saw a focus on scenarios for casual group content. And while scenarios are fun, if you're a healer or a tank, you're not really necessary for them. I personally would love to see a bit more balance in the future between implementing scenarios and implementing five-mans, so here's to a WoW future where both will shine. What about you? Are you hoping for more five-mains, or could you do without them?