Holdo is fine for me. Why dont u guys try to use her under zfinn lead? With 4* (yes i bought some shards but i believe 3* would be fine too) g8, no omega at all, and some decent mods, she can get her place within the resistance team.
Too slow? I dont think so, with TM feed from zfinn leadership she also can move fast. 5CD for her bunker buster is too long? Not really, when i tried her in arena she can use that ability almost in every turn again due to zfinn leadership that can reduce CD. I run that team against 1 of titan team in my shard and can win easily. She can inflict daze all over them.
So in my opinion, holdo is helping me a lot in splitting up my resistance team into 2. I’m not mentioning rose, since for me she’s a meh char in the film also in the game