I played WHM in the post progression phase of HW (mind you not the worst time for whm), and up until last tier. The issues with the WHM then are the same we have now. Once everyone is familiar with content and geared up WHM brings nothing to the table compared to the other healers. So I naturally expect things to be somewhat similar. (ie: people wanting more raid utility for WHM, etc. etc.)
It's also an opinion comforted by my personal experience of PF having farmed a bunch of primals for mounts recently. It's not by a crazy amount but we're already seeing more frequent WHM lockouts of primal farms since players want kills as fast as possible. I think this is stupid but yeah.