Comparing to a pitcher that has 5 years experience under his belt that's 28 years old isn't fair either.
Just think about what you have in Jon Garland. You have a guy that has, at a very young age, held down a starter's spot on a mojor league team. You have a guy that will give you 200 innings and double digit wins. You have a guy that is young enough to still get better, to learn what it takes to be a top notch pitcher. He has the physical abilities. That's the opinion of anyone (scouts, GM's, etc) who know about that kind of thing. It's just a matter of something clicking for the guy. Will it happen? Hell, I don't know. But I'd hate to trade this guy off one year too soon.
Oh ... compare him to the #3 pitchers for all the AL contenders last year. he's right with them. At least he was about Sept 1st.