Most prospects fail sure, but guys rated as highly as Myers don't usually fail.
James Shields has had one season where he would be anything other than a solid number two guy. You don't give up the farm for a guy like that.
Trade just reeks of a GM feeling the pressure to do something now.
Rotation right now has Ervin Santana as it's number two. This is not a playoff contender or even a borderline one imo.
They have a glaring need in RF and were about to fill it with a guy they would have had control of for 6 years, but they give him away for a pitcher who will be 31 in a week.