The article presents some facts, although they are selective in only focusing on Leeds and win/loss records. If the success rate for some referees looks especially favourable or negative, it would be interesting to see how those rates vary for the rest of the clubs in the competition for the same period.
Another way of looking at this would be to see the detailed statistics on penalties awarded, and for what sorts of indiscretions. This might give an insight into the sorts of penalties some referees are more likely to give, or if some clubs have an issue with particular rules (e.g. high shots and Catalans?).
Ultimately any trends from these kinds of analyses would be taken out of context so hard to draw final conclusions, although they could be useful tools in managing the performance of referees and players - no doubt the clubs and the RFL already look at something like this but a lot more sophisticated?