Problem with a big FA contract to a pitcher is the first three years you have a good chance of getting value, the last three years? If you think the Phillies are already a 90 win team that just had bad luck, it might be worth it, if you think the Phillies are an 80-85 win team then we're two years too early to make that move.
To me, build the lineup, build the farm system, get to where this team was around 2006/2007, then make the big move, but not a Garcia trade. A Halladay/Lee trade (but not Oswalt, that was a silly move, as was Pence, once you're good enough, try to sustain excellence long enough to get lucky).