This is an excellent question. I think the general answer would be the last thing TORB said, which is that the fruit in a well-made wine of this style will recede and the wine will become a little more balanced and show a little more of the secondary characteristics. Whether you like that better than when it is young and the fruit and size of the wine are most prominent, that is up to you.
I've had some Clarendon Hills shiraz and grenache from 1996-1998 with good results, though I don't think those were ever considered the "fruit bombs" when they were young. I also wait a few years on Yangarra shiraz (still drinking 2002s, and they are still great), and they do very nicely for that sort of short-medium aging, though I would probably drink them within 6-7 years of the vintage date, and not expect 10-20 years. I also don't consider Yangarra a fruit bomb, though; I think their wines are all in a very balanced style.
For those of you with an eBob subscription, the Executive Wine Seminar did a blind tasting of older big-name shiraz (Black Pepper, Grange, Astralis, Dead Arm, etc.). The results were widely divergent, some very high scores and many very low ones, and overall it was generally more negative than I would have expected.