ELL is attractive to me, because I'm used to how Stack Exchange sites work, and I'm by and large happy with how they work. And joining ELL is much easier than joining a non Stack Exchange forum and learning its norms.
But will ELL be attractive to people who don't already use Stack Exchange sites? There are plenty of other forums about English. For now, the main selling points I'd have for ELL are its Stack Exchange technology (voting, tagging, closing as duplicates). In the future, we may be able to show that our questions and answers are better than those in other forums, but we can't do that yet.