Yup i guess its all a matter of opinion, if anyone said to me lets raid tonight, and I had to do it with 4 people, id be like hmmm lets call it what it is, its a dungeon crawl night :P Id also put time down as a factor in a raid, to me a raid should feel epic in time too, I know some 'raids' in wow are short, maggy etc but those had the scale to go with it. a 5 man dungeon to be a raid should be massivly epic in size and scale ala ulduar or time consuming (not in a boring grindy way)