This list assumes one big thing: That other teams valued Liriano at the same value the Twins did. The reality is that Liriano is having a terrible season, isn't the pitcher he was 6 years ago, and will never be the pitcher he was 6 years ago. To think otherwise is foolish.
A team that has a chance to go to the post-season will look at Liriano's 5.31 ERA, 1.44 WHIP and say "He's not worth it." Every other pitcher that has been traded for better prospects is BETTER than Liriano.
It was time for the Twins (and a lot of Twins fans) to get past "what-might-be" for Liriano and realize he is what he is. A inconsistent pitcher that has had an ERA over 5.00 three of the past four years. Twins are lucky anyone took him at all.