Disclaimer: I absolutely hated ED when it came and continued disliking it until the introduction of IOs.
Now, I'd never trade back IOs and Incarnates for the pre-ED era CoX or even go back to no ED with IOs and Incarnate powers intact. In hindsight, I think ED was a necessity for the future developments of the game, but its implementation had bad timing (two years gap to IOs) as well as bad PR.
Here are the top three reasons why I think ED is a good thing for the game:
[*]Like the name says, it promotes a bigger diversity of enhancing strategies. Without ED, playing as a Scrapper your standard slotting was 5-6 Damage SOs in your main attacks and maybe an Accuracy if you need it, 6 Res/Def in your main Defensive powers, 6 EndMod in Stamina, 6 Rech in Conserve Power (to avoid needing EndRed), 6 Rech in Hasten (to avoid needing Rech), and 6 ToHit in Focused Accuracy (to get by with 0-1 Acc). The issue with this was that basically all powers were either 6 or 1 slotted, and there was absolutely no variety in builds whatsoever. If you skipped Hasten, you'd need to devote 2 slots of Recharge in each power to achieve similar recharge rates (at a cost of 66% base damage). Same with Focused Accuracy or Conserve Power.
After ED hit, the gap between alternative and optimal strategies wasn't quite as huge so you weren't comparatively gimped by going for 3xDmg, 2xEnd, 1xAcc as opposed to the popular 3/1/1/1 slotting, whereas before ED doing the 3/1/1/1 slotting because you didn't want to go with perma Hasten, Conserve Power and Focused Acc/Tactics, you'd be doing a whopping 33% less damage than someone with 6x Damage (not to mention, your recharge rates and endurance reduction would also be worse).
[*]ED allowed the introduction of IOs which bring us a huge variety of ways to build your character. Sure, the gap between a fully optimized IO build and an SO build is vastly larger than anything possible in the pre-ED world, but this time around you'll need to spend time designing the build, optimizing it and collecting the gear. The gap in power comes through investment and commitment, as opposed to the pre-ED world when any SO build cost exactly the same.
[*]We have actual character power progression now thanks to the two previous things. Before ED, the progression was incredibly simple: get the cookie cutter slotting when you hit 50 and you're done. Currently we have several levels of powerful starting from "pretty powerful" at level 50 with generic enhancements, going up to "basically a god" after having fully optimized IO sets and Incarnate abilities, and content to match this progression.
With Incarnate abilities partially breaking ED as well as set bonuses, there's absolutely no reason to repeal the change. The way ED exists right now forces trade-offs and promotes unique build designs, which I think is great. I'd much rather have a variety of ways to design a powerful character rather than a 6 or 1 slot world where you fully slot 13 powers and leave the other half unenhanced.