Bloc judging actually becomes more potent under the CoP, just less transparent. Under CoP, just one judge can have a huge impact on the scores. If there is indeed a certain group of conspiring judges (or even just one corrupt judge) favoring certain skaters, the results will be easily manipulated without anybody knowing.
Keep in mind that statistically, the sum of scores has no real value, because it doesn't measure a truly representative value of a set of scores. Statistically, the sum is only a preliminary step in calculating a meaningful value in a data set. The sum itself is not meaningful because of the fact that just a single score can skew the entire data set. The ordinal system is more robust than the CoP, and more of a deterrant to cheating. Under CoP, the random count of judges' marks may or may not discourage cheating, but it definitely won't guarantee that it'll stop. And once any corrupted marks get into the CoP system, they will have a huge and unfair impact on the results. All it takes is one judge.