A test server for iTOS wouldn’t solve things, they’re already going to make a reset even that will allow everyone to reset and test everything they want to, just like kTOS, the only thing is that we’ll get it when it’s done.
A test server purpose isn’t for users to test things to themselves, it’s for users to test things for developers and feedback-wise currently a korean test server stands as a best option for them, even though a greater community would give more feedback.
And having a reset event on the live server when everything is right is actually better than having a single reset handed out because everyone already tested everything on a separate server. In the live server you have opportunity to fix build and stats of all your characters and as well test them with good weapons on real world usage such as PvP and Earth Tower runs.
The reset scroll was given one time as an unique event, along with usual January vacations, that made a lot of players come back. I think the smarter choice is to do the same, once everything is read they will do a reset event for everyone to test all builds they want to and as well reset and test everything. And it’s a great thing that a lot of hidden mechanics are being removed, documentation-wise.