I've actually flip flopped on this situation. I wanted the team to focus on Berrios because he was the safer sign. I still think he is the safer sign, but Buxton is that game changer that the team needs. That any team needs. I'm not worried about him being the next David Ortiz, I'm worried about him becoming a healthy Byron Buxton. When he's on the field, the team is so much better. These types of players simply don't come around very often.
I'm with @USAFChief in that expecting Buxton to sign for $15M guaranteed is lunacy. I like the idea of incentives to trigger a bigger payday. I can understand why Buxton wouldn't like that, but if he's betting on himself, then a mindset of these being achievable isn't unreasonable.
What this team can't do is let him walk. If they can't sign him, they need to trade him. That's not my preferred option, but it's a lot better than getting a comp pick for him.