I got a theory coming out from reading the lore deeply, going into the classes(current and previous) and just straight up looking at all the skills and stuff. it's said in the lore that runic magic is different and may have an entirely different origin from elemental magic, possibly more ancient. I'm thinking probably the classes(elemental magic) developed some of their skills as they were studying those runes. Frostborns studied Wolf's Blood which is why they can see the outline of enemies, and it might just make sense with how the Wolf's Blood leaked outfit is clothed in a way suitable for the cold regions. Conduits probably studied Teleportation but they never got to perfect how to fold space but they did learn about rapid charging of mana and power surge. Pyromancers studied Flight obviously, using the strength of flame to imitate the propulsion generated by the rune. Toxicologist studied Shadowstep and substituted the shadows with the shroud of their toxic clouds, they probably learned more about invisibility through the Invis rune so that's why the duration of their invisibility is longer than what the Shadowstep rune provides. Stoneshapers maybe studied the springstep rune in reverse to push themselves towards the ground instead of off it as at their core they need to be grounded or, this idea thanks to Mr Lemonhead on the discord, they studied it to help them lift the boulders of the ground. Tempests studied Featherfall and applied the strength of their tornadoes to propel them upwards. Now looking at the outfit leaks it might be possible for the Crackshot, Bulwark, and Scavenger classes to make a comeback because they somewhat follow the pattern of having progressing outfits of three levels you can observe with the already existing classes(Lightning's Paragon, Prince of Pestilence, Earthen Rumbler, Heaven's Majesty, Winter's Vengeance, Inferno's Champion). I'm kinda not confident with Scavenger but Crackshot and Bulwark I strongly believe might come back in some form. and I think if they do become classes then Crackshots would have studied the Dash rune(the leak outfit based on the rune sports similar streamlining with the crackshot and tempest outfits) and Bulwarks the Chronomaster(with how at the core of the class is recovery and defense, and the rune has recovery and immunity), Scavengers in depth with Invis(but again I am not so confident with the Scavengers)