So after two heroics that ran with completely open roster, i came to following conclusions:
- opening roster was great for majority of player base as they were struggling with the limited rosters they were given each heroic
- opening roster was terrible for people in 5* land who saw heroics as the only chance of playing with something else than 5*
with that said, in order to make heroics enjoyable for both type of players, simple solution would be to just limit rosters to 1-4* and completely lock out 5* from them. I hope devs will take this into consideration, since its an easy fix and the one that would benefit us all.