Ephinea was launched in August 2015, so it's approaching 2 years old -- relatively new compared to the other well-known PSO servers!
The server was founded by Sodaboy and tofuman, shortly after Sodaboy has recently returned to PSO development after being bribed encouraged by tofuman. Sodaboy used to work on SCHTServ back in the day, and was administrator temporarily there before Crono117 took over. tofuman was a developer for the Eden private server and had been working on Tethealla for a while before Sodaboy made his re-appearance.
The server did indeed take off after the SCHT data loss, about 2 months after it. I want to say it was coincidental, but Sodaboy will have to answer that one for you!
The devs didn't actually "dislike" anything about the other servers, Ephinea was actually setup as a server so that Sodaboy/tofuman had guinea pigs to test their Tethealla updates in real-time. That being said, the server was introduced as one to emulate the original vanilla BB experience as other private servers had custom items, game-breaking changes and donation incentives. Obviously it's changed since then to make PSO more fun and enjoyable for everyone, but it still plans to stay true to that formula (no custom equipment, no donation incentives, the vanilla balance*)
For proper in-depth answers it'd be best to get answers from Soda and tofu themselves, but I figured I'd pass along an answer to make it easier to sleep tonight. :D
* There's been minor tweaks and changes along the way, but it's still 99.9% the same.