Im actually surprised Peacock hasn't made it a closer race. IMO, the top 5, no matter how you rank them is Harper, Rendon, Purke, Cole, and Peacock.
There's a lot more talent but guys like Hood, Meyer, and Norris IMO have bigger pressing questions or haven't proven enough at a high enough level to push any of those guys down.
In total agreement with you here(crossing my fingers for Purke to sign). Hood to me is not top 5 because he hasn't proven he can perform in AA plus he's projecting to be a corner OF bat right now and most likely will play left field, not a premium position. Meyer(might have the highest upside of any pitcher in our organization but hasn't thrown a pro pitch and is inconsistent so I can not put him ahead of a guy who has proven himself in AA). Norris didn't have the breakout season many were expecting, Peacock has had the breakout season. Peacock was number 42 on BA's midseason top 50(
http://www.baseballamerica.com/blog/prospects/2011/07/midseason-top-50-prospects-list/) there's no way he's not one of our top 5 prospects.