I think there are at least two glaring problems with this paper:
1) Not sure if this is just inexcusably poor writing or whether it's actually part of the theoretical foundation for the analysis, but the paper expressly states more than once, and does seem to rely on the assumption, that it is "evaluating players for every event that happens on the ice." I.e., all stats kept by RTSS. Obviously those stats are severely deficient and incomplete, which means that if the paper does in fact assume that the stats kept by RTSS are coextensive with all meaningful on-ice actions then its results are going to be skewed, probably significantly.
2) With the exception of a few express attempted adjustments to the RTSS stats (e.g., MSG shot locations), the study makes no attempt to differentiate for quality of the on-ice actions that are recorded as stats. In a sense this criticism is included within #1, in that the idea is that just as RTSS fails to do, so THor does not make any allowance for the difference in quality of shots, hits, etc. etc.
I'm new to the boards and expect there may be some disagreement about this second point, as in many ways Corsi and Fenwick suffer from the same problem.