I guess then, it depends on execution. If you're combining both of these numbers into one single metric of "goodness", then you'll just be accomplishing Pahalial's point of "legitimizing 'poor taste'". If, however, you can expose this information separately and well, then perhaps it will add value.

Personally, I'd like to break down the "rewatchability" metric into more components, to really get at the heart of the matter, like others here have commented. Pace, quality, fun, emotional impact, length, genre -- these are the things that really matter. But now we're getting into movie geek territory.

Speaking of movie geek -- I can't believe you left out the most interesting thing in that blog post. Where can we see a breakdown of what movies are where in that scatter plot? I want to know what those outliers on the high quality / low rewatchability scale are!