As far as I can see the only thing adding Kai-Wei Teng does for the team is to satisfy some of Cranes desire to be a player for prospects from the orient. I once put a sign on a closet in a corner of my back room that said "The Orient" and whenever someone called me looking for a personnel guy they couldn't track down I could always say I thought he was on his way to the Orient. Worked great.
I never question our pitching acquisitions. The pitching braintrust is right more often than wrong. Remember that even Cole wasn't a guarantee and many thought Verlander was well past his prime every time we acquired him or resigned him including our GM Click.
I don't mind the deal at all. This Astros team has too many relievers without options. The Astros' pitching scouting and development team deserves the benefit of the doubt. Villarroel had a very very low ceiling. I can not see any scenario where he becomes a starting player.