What I would like to see is old boss fights rehashed into repeatable strike missions, and a new class with expansions. Rather than inflate the number of elite specs and creating balance nightmares, they could easily release a single core class, or a single core class for each armor type, and then add elites to it with expansions.
New strikes, fractals, with new mechanics, and of varying difficulties (including pushing the boundary past HTCM) would also be highly welcome and refreshing.