Well for me the rating discussion is actually more twofold. There's the issue of being able to actively use the ratings to narrow the potential entertainment you're looking for, but the primary one still is to be able to rate as accurately as possible, and without breaking a sweat at that.
Concerning how difficult or demanding H.264 is I'd say that's neither here nor there. A release in this quality should never come alone, and as such it should always only be a service for those who care about such things. Personally I
hate streams with a big H, but I respect that making a movie successful to a great extent is about hitting the largest possible audience, and for that you need good as well as poor quality releases.
Concerning the idea where you comment on what works and what doesn't about a specific movie, they have been using that at
www.Newegg.com (which is probably one of America's largest internet hardware retail sites) for a long time. Does it work? Well, I'm split in two to be honest. For the generally immature community that is World of Warcraft, serving everything on a silver plate that says "Write cons here" and "Write pros here" does make some amount of sense, but I'd hate to be limited to putting it up like that. The content of my comments vary greatly depending on what feedback I wish to give, so to me it would definitely be a limitation.
I think the current PvE, PvP, Old Instances, Server etc. categories work fairly well, though indeed there's no Machinima. But isn't this category a tough one to figure out? I mean music is often Machinima, but so is story-line, and even a PvE movie can be Machinima if made in a specific way. Instead, how about adding additional Top 50 lists for each category? Few would want to watch more than the 50 best of each category, so I reckon that'd go a long way, and with relatively little effort and risk from the programming team.