Back in Diablo 2 Classic Rares ended up being superior to Uniques, minus a few specific ones (soj). When LoD came into the picture this changed, my super bad ass 150% ed 20% ias, 141 attack rating, P Skulled, 1 barb skills executioner sword became so obsolete (aside from the fact it was only 150% ed Executioner sword and not a 300% ed Colossus blade) as the Grandfather was the best sword in the game for long while (legit sword that was).
Then in 1.10 came and the potential for rares out doing uniques opened up again with 300% ed was actually allowed on rares, But the age of runewords emerged. BotD, Grief, beast, all came in and shattered the dream of finding that super rare Godly rare item.
In Diablo 3 we can only hope that godly rares can out do uniques or legendaries, whatever they are being called. In a game where you get that fun fresh every time random layout of the map and monsters, hell even random monster effects and those beautiful never know what is gonna drop item that could be great or garbage. If there is a best item for any slot that is always the same ( unique ) and not a random ( rare ) attributed item I feel the game will die in both character, sense of random freshness and economy (soj 2.0 flooding the ah).
So please let Rares have the potential to be the best items just like back in the good old days of Diablo 2 pre LoD.