I've only remembered that there was some kind of problem with it

But, I now also remember what was the solution! You've made a platform.. somewhere far far above on the ground. Maybe it would be nice if players would spawn on a platform like that?
But to evade the problem with /resetspawn and constant spawning on the platform after dying again and again.. there could maybe be a teleport from platform to some.. hmm "mid-air" location that is not too high above the ground? For example let's say that the spawn platform is at 15km above the ground and there is a teleport on it which transports you to the location 15 meters above the ground at the airport parking :P
That would prevent registered players to re-enter the platform and also it would prevent constant dying, problems with spawn and crashing..
too complicated? xD
Maybe all of this could be done with the current ocean-spawn :P