I see, this means that the Hunter's Mark must ideally be cast on the first turn. On the second turn, the target with the Hunter's Mark must be near another potential opponent who will get the Hunter's Mark off if I take out the first target.... Hmm, that is indeed a few too many conditions that need to be met. I think you are right. Colossus Slayer is better because at least you have the BA free, which is more versatile.
Yeah, also if you are in a single target or boss situation you will still have colossus slayer once per round assuming you can hit something missing health. We'll have to see what release looks like to see if options beyond colossus slayer become more generally viable.
