TL;DR - how possible that we will get the 6th class for our characters to play with any time soon?

Previously I planned by the end of 2018 to have all 15 characters on my account. I created a spreadsheet with all of them being described in details - which class should they be, what resource should they be based on, what gender, what role and game mode they have to stick to the most. The plan was to make them all masters in all crafting skill lines, train their mounts, maximize their inventory capacity, basically make them all complete. I even started to collect all the set pieces in advance. So far I have 7 characters in ”work in progress” state, with my 8th in already ”complete” form (almost).

However recently I thought, what if we will get a new class in the game with some update in the future, as we got Wardens with the Morrowind chapter. Since there is no option of changing the class on already created character, the only way to play new class is to create a new character. And since I was planning to get all possible slots (15) filled, the only way for me to enjoy new class would be to delete one of my characters that I put a lot of hard work into. Hence here is the question - should I stop on 8 of them and leave a room for future?

I know that everything is possible, and devs may have plans on adding more classes. That is why I am asking such question hoping that some veterans or players that keep an eye on updates, changes and messages from developers may have some thoughts about this matter.

Thank you in advance!