Yeah jung I hear what you're saying with respect to Iggy...
It almost seems that unless you shine brightly and play better than expected when you're brought up, you're sent back down pretty quickly. The good news is, if you truly make the most of your opportunity (ie: Will Middlebrooks), you can earn a spot.
Same with Pedro Ciriaco, guy came up and just played awesome. Iggy comes up and can't seem to do play well. Lavarnway played awesome the year before last when we brought him up, but last year couldn't do much of anything.
No doubt your point is valid, though. These guys would most likely get good, but just can't seem to do so right away and need more time/trust etc
Word