Mermail + Atlanteans have done so well in TGC for years, Duel Links hasn't caught up to the TGC's standard yet. I cant imagine them not being tier 1 tbh
Mermails have been overhyped. They didn't get much support. Kindda like Dark World, they were hyped coming in because they did well in the TCG, but without proper support they wont be top tier.
no dragoons, no linde. not even a good engine to search - tier 2 at best. hell even vampires search much more than these waterboys. i would love to experiment with fish mermails with atlantean and cranium fish + ties of brethren (maybe atlantis aswell...)