This is basically what was concluded in another thread:
Raremob:
So you’re sayin glaives are given to rogues because they are terrible in tbc to make them better?
No, I’m saying that Rogue is actually really good in Classic, so giving them a Thunderfury isn’t a waste. Most guilds are going to give a Thunderfury to a tank, of course, but on a Rogue it is at least useful.
Fury Warrior is terrible in TBC, by contrast. They’re a total waste of Warglaives.