Optimally, they could create 4 new tint sparkle variations & then the original MT sets can come back with Legion Classic.
This would mean that everyone could obtain 4 more sparkle variations & then the people who really wanted the old ones, could grab it come Legion Classic (and wait for the great classic/retail transmog merge).
And optimally the new ones would be better than the old ones since, it’s good to release new and improved content.
Examples of new tints: Rainbow, golden, pink, teal (but more on the green side), flowery (flower trail), fel (but with an intense fel fire trail)… the list goes on and on. It just should have equally awesome trails. Having 4 new tints with fun trails would bring a lot of new fun diversity to the druid class.