Agreed, we should keep an open mind about them. Pena needs to just bat left handed, he seems to me a left handed hitter that wrongly thinks himself a switch hitter. I could see him and Pastornicky or Pastornicky and La Stella making a decent platoon at second. Further, it seems we are higher on Pastornicky than most on this forum. I think some wrongly assume he'll be a bad defender at second because he is so bad at short. But thus far his DRS at second is better than Pena's (while a small sample his defense at second was also fine in the minors).
Personally, I like the speed Pastornicky brings, if he can hit .275-.300 he has the speed to steal 30-40 bases (depending on where he hits in the line-up). This is also why batting average should be considered with him more than simply OPS (same goes for other stolen base threats). Hopefully the knee injury doesn't take away from his speed.