For all the accomplishments you point out about Stubbs, I'll counter with the following:
He was out hit, SIGNIFICANTLY by four other guys on his team that also made their professional debut in 2006. Scouts had serious questions about his bat and thought the pick was a reach by the Reds.
WMP had 26 HR's in 336 AB's in 2004. At age 22. Wanna see the list of guys in MLB history that have done that? If I were running the show in Boston, I'd start him in CF over Crisp. Yes you'd lose a little defensively, Crisp is a good CF, but the gain offensively would be huge. Crips has 43 HR's. Lifetime. Pena could hit 43 this year if he got 500 AB's.
As for learning on the job, it can take years. I wasn't good at my current job until 3 year ago. This is my seventh year here. There was a big learning curve from my previous career to my current one, and very little training.
The main reason I don't give Stubbs the benefit of the doubt is that he never should have been selected in the first place. I hope he proves me wrong though.