As it stands, even with the fix to the spawning of wisps in the desert, there is no point in going to the level 90 wisp colony.
In order to achieve max exp/hour you are needed to do chronics.
As the length of time taken to get back to the level 90 wisp colony is relatively greater than the time taken to get back to the level 85 wisp colony, it is more efficient to stay at the level 85 wisp colony.
So that the level 90 colony can be used as intended, I strongly suggest a new teleport be put in place.
Although I realise the carpet rides have been streamlined for this process, I believe it is truly not enough to make it worth training at the level 90 wisp colony.