I'll summarize my opinions here the same way I've summarized them elsewhere:
MLP: EG is good in the same way as The Super Mario Bros. Movie. What I mean by that is this: I have a fondness for the Super Mario Bros. Movie, even into adulthood. I don't think it has remotely anything to do with Super Mario Brothers, my like for it, but rather, nostalgia (of course) and the fact that within its universe, it's a fun kids' action movie. Therefore, it's good, SEPARATE from its commercial tie-in.
EG, likewise: Good writing, one of my favorite songs, but I don't consider it all that much an MLP thing. It seems more to me like what they could have piloted as a legitimate high school themed cartoon. By tying the two together it felt like an exploitation. They could have just as well done this as a pilot episode of "Central Colt High" or something, and not made the characters "human Twilight" etc, and I would have found it legitimate. It's how much I feel manipulated by the film that bothers me. I have no qualms with the content, just the execution.
One legitimate connection between the two is the Sailor Moonish feel I got from it. All the movies (long episodes) have had a very good Sailor Moon feel, and if you want to jab me in the nostalgia, it's a pretty effective route to take.