Not having worked any RYRs for a few years now, I have no axe to grind. Still, I reckon it would be instructive to "work to rule" just for a week with RYR and see how they like it. It is, after all, completely reasonable to give only the flight planned levels, duty runways and standard speeds. None of the above can be termed "taking it out on the pilots" since they're being paid to do a job of work and no one is suggesting making that any harder for them!
If doing a favour for RYR will increase an ATCO's workload, at a time when most of us are pretty damned busy most of the time, it makes sense from a safety perspective NOT to do the favour. If that seems harsh, tough doodoo people. Most of us WANT to give our best and probably do more favours than we should.