A very brief thought on the expansion of instant replay

Opening Day 2010 had its fair share of exciting moments --- Jason Heyward's dramatic home run, Mark Buehrle's insane defense, and Jarrod Saltalamacchia's walk-off, to name some highlights. However, there were two other notable plays that have gone under the radar today. Actually, they were pretty much the same play. Both Nate McLouth and Rajai Davis made disputed catches in the outfield, and in both situations, replay verified that the ball touched the ground. Now, we all know that umpires have an insanely tough job, and it's only human to miss a few calls every once in a while. However, it brings up an interesting point --- if we have instant replay installed for home runs, what exactly is holding us back for using it on plays like these? You could make the argument that if we open it up at all, it could be abused by overuse (it ruins the spirit of the game, it would wind up taking too long, etc.). But if the technology is there, why are we not taking advantage of it? If the umpires are convening, anyway (which is what happened with McClouth's catch), shouldn't they take the few minutes to verify it with video? As the season goes on, I'm sure that the debate over the proper use of replay will heat back up.

EDIT: While I couldn't find an online clip of Davis' trap-catch, here is the play by McLouth, courtesy of MLB.com.