To get McCoy, we needed to send something of value. If he was cut, there was nothing to say we could have signed him. So we were forced to send an asset.
As for Woods and Kiko, at the time of the trade Kiko was more expendable. What makes our defense works is the D-line. The linebackers aren't as good without the D-line. We need offensive playmakers that can make plays with our qb situation. And that is why Woods was kept.
If they knew they would get Harvin and Clay, I think Woods is expendable. Harvin deal is for 3 years if they want and will relieve pressure off Watkins. And Roman plays mostly 2 wide receiver sets with multiple tight ends/fullbacks so it will be hard to get them all on the field.
But they can't predict the future and there was no guarantee those guys would sign with us.
It would have been more interesting if they didn't leak the trade until league year started. They would have had the free agent visit window before the year started. If they knew they might land Harvin, they could have switched up the trade to Woods. Not sure Philly would have waited but makes you wonder if leak may have prevented any possible switch last minute.