Truth follower. The combination of Truth Follower and Analysis of the Truth allows you to keep a monster like Hackster going on indefinately, as you can remove his cooldown every turn and give him stamina regeneration if he runs out. I have defeated many premium dungeons with Bo Tai, Hackster and a decent hitter.
Going for Refuge is IMO overrated. Bo Tai is not immune against stuns and freezing, so possession is the only real skill he can remove from your allies because he's not hit himself. But for this you would have to run him first or at least second (before your damage dealer), but is he really a denier? He's quick and he can protect you against stuns, freezing and possession, but my trouble is usually with stronger teams where I want to keep them from doing damage, hacking and of course I want to control VoltaiK. So you would have to use him with another denier, but then you have no support to load up with team speed runes so chances are the enemy denier is faster and will freeze or stun Bo Tai.
And anyway, if you choose Suns and Moons protection you can just use the right protection move against whatever your enemy throws at you.
On defense Bo Tai is utterly useless anyway. He'll never use the move you need.
In the end, I'm very happy with my moves - Suns and Moons protection, Analysis of the Truth and Truth Follower, and run Bo Tai as support.