I went with a mix of AE and PHB classes for our Oathbound game: Fighter, Ranger, Rogue, Barbarian, Psion, Psychic Warrior, Akashic, Champion, Greenbond, Magister, Mageblade, Oathsworn, Totem Warrior, Unfettered and Witch. The Runethane seemed inferior in almost all regards to the Magister, so he was nixed, and the Ritual Warrior seemed really weak as well. Not a fan of the Warmain, as its just a boring fighter with even fewer choices. One player wanted to play a dragon, so I made a lesser drake class to 20. I made a bunch of channeling related feats, so that people of any class could be a priest.
The party consists of
Human Magister
Picker Ranger/Rafter (specialized explorer prestige class)
Thorn Greenbond/Ranger
Sky Drake paragon
Human ranger/Akashic
Nightling fighter/rogue