Since this next season will likely be a season of reboots and may or may not give us a new class, I have a suggestion.
Allow Seasonal Tagging. Seasonal tagging doesn't take the slot of your normal tag. Different from normal tagging of gear or the "Fughar's Timepiece", allow us to tag a lower level character (main 59, thus the tag can only be 58 or less), then allow tagging of the Tuvala gear the main has and converting the tagged character into a "seasonal" character until untagged. In order to "tag" the tagged character needs to have no gear equipped. This way you can't tag a level 66 to a seasonal character and pull them onto a seasonal server.
This allows for 2 not just 1 class to be tried out on Seasons, makes it so you only have to level Tuvala gear once instead of making multiple weapon sets to try out the new classes.