So I farmed those weapon illusions for the Shamans. But in Shadowlands since we’re getting back both Flametongue and Windfury, I don’t see why I should keep them.
I normally like them because they help me keep track of where my character is when we have to stack up, also the streaks look cool when you swing.
I’m not sure I understand…
Weapon Illusions are like tmog for enchants.
Before they got rid of our Shaman swirlies, they put these on bosses we can farm.
Now the illusions for Flametongue and Windfury are going to be useless after Shadowlands hits because we’ll already have them.
I know what illusions are and where the class specific ones come from. 
My confusion was with the sentence:
Because as far as I know, not every spec has Flametongue and Windfury, right? Yet those illusions are for any spec of Shaman. So why wouldn’t you keep them?
Every spec is going to have both, Flametongue and Windfury will be available for all specs of Shaman.
Surprised they didn’t put in a modified Rockbiter or Earthliving either…
Ohh I’d like this 
I know they have Rockbiter weapon illusion from Tectus, but I dunno if they have Earthliving?
Because they could be gone the next expansion?