They were leaving early when the park was open until 10:00 PM. Though I agree they are closing too early when the hours change to 8:00 PM in September. Epic gets that early crowd like AK, and many people are worn out by 5:00 PM like at AK, plus there's not all that much do to if you're not a big coaster fan. Of course, that early crowd thing might change once the newness wears off....and/if AP's get a reasonably priced three park AP.
Presently, you can get lots of rides in on that early admission hour, especially if you avoid Ministry and DK Minecart (sometimes opens during EH) that often have early 'issues'. Once AP's arrive, and the park isn't mostly tourists, I can see Epic behaving more like most of theOrlando parks do, except for AK and their animal orientation.