I'm one 3* Rainbow Shard away from another 5* character thanks to new update! I haven't been too lucky with my Rare Soul drops (still searching for a sentinel souless demon..) but I have some characters worthy of being a 5*. My choices are :
Holy Smoke Eddie
SoL Eddie
Wickerman Eddie
Mummy Eddie
Pharoah Sun Spirit
Warrior Troll
Assasin Troll
Corrupt Harpy
Assasin Bomber Boy
Assasin Souless Demon
Warrior Souless Demon
Masked Harpy

Sorry for the long list, but these all look like worthy characters