For missle attacks, I can see it as one roll=one attempt to hit. Aiming is harder, plus then there would be the question of arrow expenditure otherwise. For melee, no way. Six seconds is a frickin' eternity in a real fight, be it with fists, swords, or anything else. If we were talking one attack per roll, then we should be talking about .5 second combat rounds or smaller.
Generally I look at melee combat the way I see martial arts combat (the only combat I've ever seen, really); you have lots of blows happening every second but most are countered or are just tests to feel out your opponent's speed and power while simultaneously protecting yourself as much as possible. That attack roll represents your attempt to do some real damage and push past his defences or take advantage of a perceived lull. You miss, or hit but do little damage.. you mistimed it. That's why touch attacks are so easy to do: you're not worrying about pushing past or seeking out holes in defences with enough power to do some real physical hurt instead of scratches and jabs - you just need to encounter the body.
Most of the inconsistancies with that view vs how combat actually works in D&D fall into 'what makes good game play' vs 'what would be a real simulation of combat'. If we were really concerned about the latter, some attacks would be almost trivial to perform and affect character way out of proportion to how the game should be played. Many, many more combats would end with character death. I'm more concerned about what makes a game fun and fast than I am with strict simulation. D&D combat doesn't break my suspencion of disbelief enough for me to put up with the hassle of a more 'realistic' combat system. I've played enough games where such attempts were made to know it's generally not to my taste.