In the future, Riot should do another Freljord even and herald with a champion that's an actual Watcher. I've always been a fan of the Freljord's lore and seeing how well they delivered the Bilgewater event, I'm quite sure that it would spectacular.
Im not against playing with a Watcher.
Overall I think a watcher is a bit unlikely,because of 2 reasons: 1.Riots archetypical approach to champion design. Champs are generally made to be distinct and offer a unique archetype that no one else represents.While the whole elder-god-vibe of the watchers might be something new,a watcher might step too far into vel'kozs beholder archetype(not saying it is impossible though since the watchers are quite different looking with their hands and all)
2.It would kinda devalue Lissandra as the big bad of the freljord.The watcher would stand above Lissandra thus reducing her to the second fiddle of the frostguard and I dunno if they want to do that already.
In the end it is not impossible,but I think it won't happen in the near future.
