Biggest problem with EP is that you basically had to have a fireteam going into it or you'd never have enough players to get very far. It was a fine event but really demanded you have a full or nearly full zone of players all working on it to progress it far enough to be worth the time.
Wait what? That NEVER happened for me. There was always people there and if you started it with others just roaming around they would instantly jump in.
If you wanted to cheese the system you would and the others invite someone in and then you could get up to, was it 12? (we usually, at the beginning at 7-9 players running it, which at the beginning was almost needed to beat the bosses. After Bungo finally addressed the cheese and we progressed up a bit a 6 person team of rando's semi-fairly easily completed all 7 waves. But yes at the begging without more than 5-6 it was very very hard for normal (non-fireteam) groups to complete all the waves, ESPECIALLY when the wizards popped on Bok Litur, ironically the shriekers seemed easier on Damkath to deal with as we had more areas to hide to take them down, BUT they did eat up the clock faster than the wizards.
90% of my time spent trying to run EP would be me doing it solo or with 2 other randoms in the zone if I was lucky. Even then, most of the time, people would leave after the second wave anyway.
It's the kind of design meant for zones that can hold more than 9 people max. When you start splitting the playerbase in your "multiplayer" zones too much, you're going to end up with a lot of instances with very few players in them.