Marco, I think there are two big unknown issues that complicate the answers to your questions.
The first is one that has already been brought up -- it's not completely clear what qualities in a young pu'erh will mean awesome qualities in an aged pu'erh. Will all pu'erh become gold after 10-20 years? One can only hope.
The second one is this question of drinking young pu'erh. I have heard some say that this trend is a recent one, perhaps on-set by the pu'erh rush of the mid-2000s. Even if this trend is not true, I have also heard people say that more manufacturers have created (or at least, marketed) their teas as "drinkable now." The great unknown question (and most worrisome) is what did these 'changes' in making the tea drinkable now do to the long-term aging potential of the tea?
Although it's nice to enjoy a cup of young pu'erh, the goal for most of us is in the aged pu'erh. If you sample teas at various ages, you will begin to develop a feel for the pu'erh "spectrum" of age. And yes, you may actually prefer something mid-age (5-10 years) over something older. Or there may be times when you just need a kick in the teeth and brew up a current-year Bulang.
In this case, each tea will be different. The tea itself, its packing style (loose versus tuo versus beeng, etc), and its storage condition will directly affect how and how quickly it ages.
Incidentally, I have heard it said that pu'erh tea will peak as well. However, I think these times are usually quoted in the 30+ year range, so perhaps not a pressing concern for most of us...
You'll note that many of my statements say "I've heard..." -- there's a lot of rumor and passing of information, but it's usually quite difficult to find an original source or something grounded in anything but farmer or seller speculation - not that the latter is a bad thing. Remember that pu'erh is excellent for weight loss