Well yoshi-p did say that according to his "data" in heavensward not many people changes were made to the tank/healer population and thus he introduced 2 MOST POPULAR job as DPS in.

Worst possible scenario: A month after 4.0 tank/healer populations dropped really bad. People complained and yoshi-p comes out and apologize and tries to balance things out. We might get new tank/healer jobs(nah don't think so..) or they might buff or give us back our skills they took.

As a Dark knight main though, i rather have back scourge and dark dance and you can take bloodspiller and shove it.