Here is a discussion of a significant issue. Should you up the teaching load of professors who are paid X% of their salary for research, but do little or none? In my view, yes. If I am paid 40% of my salary for research, and I devoted 5% of my time to it, then I am not doing 35% of my job. Why does this sound harsh? People can get stuck on research for a few years at a time, so there is the danger of mistaking a temporary lull for a steady decline. If we look at it over the long range (3-5 year periods), then the faculty member should have something to show for this amount of time. Even if there is a long term project, then there will be at least some spin-off articles. It sounds harsh because the variability in research can be so extreme among members of the same department. In contrast, everyone teaches, at least preparing, grading, and showing up, so the differences are never going to be as glaring. I suggest that this seems harsh because we pay lip service to research, are all presumably doing it, but we tend to be over-generous with our friends and colleagues who simply are not that accomplished.
This depends on my perspective, of course, that a person hired for a research position should be willing and able to do research. We have over 100 applicants for one position.