Oops, I meant to add an initial comment. Bringing things back from exile generally isn't okay. I'm experimenting here to see what everyone else finds acceptable. Thoughts?

­Arc-Slogger would be able to go off every turn, and be useful for more than just the finishing blow. Ouch.

Hmm. Well it makes some combos: as well as Arc-Slogger it can be used to make temporary flickering like Roon of the Hidden Realm or Mistmeadow Witch permanent if you want it to. Also goes well with Banisher Priest / Faceless Butcher effects. In terms of whether it crosses a boundary it shouldn't, let's see: flashback spells go back into your library. That's the only category of self-exiling cards I can think of which are particularly affected by this.