How are we comparing apples and oranges? Everyone complained about Lackey before he got here because he pitched in a pitcher's league, how is Santana any different? They're coming from the exact same team.
Sure, you may not be paying as much for Santana, but you're also committing talent. Lackey didn't cost a middle of the order right handed bat.
The worst part is that if he does not work out, you lose Youkilis, and you can't even offer Santana arbitration because he'll make 13 million in an arb case.