Not entirely. Loot drops are anything but random in the raids I've run. So far, we've killed Staghelm 5 times, 4 times out of the 5 the warrior/hunter/shaman token has dropped (only 1 token in 10-man raids), the leather boots have dropped at least twice, and the caster leather legs have dropped at least 3 times (even the feral has them).

Other bosses are similar, we get the same two pieces almost every week, and it's a rare thing to actually get the piece someone went to that boss to get. I'd say out of the 10-15 items a boss might drop, we reliably see 3 or 4, and almost never see the rest. For example, we've killed Shannox every week since FL was released, and we've seen the cloth boots several times, the mail helm a few times, and the leather gloves and shoulders (actually sold a few of the shoulders since they're BoE). Wowhead.com lists the Skullstealer Greataxe and a caster ring as having the highest drop rates and yet we've never seen either.

So I don't think the random number generator is really all that random. I've been raiding since the beginning of wrath, and for the most part the bosses will drop the same small subset of its loot table in the raids I'm running (generally with the same group of people) every week. A good random number generator wouldn't have you reliably getting the same drop 60% of the time, there would be a more *random* distribution. Warcraft's random number generator seems to be seeded with the account IDs of the people in the raid.

Either that, or the loot generator checks to see if it's possible to drop items that cannot be used and weights those much higher. A logical reason for that would be to force people to run the content more times to get the loot they may want.

When I started running T11 raids in cata, there was another hunter in our 10-man as well. Since no ranged weapons were dropping, I ran arenas with a friend until I got enough points to get the PVP bow (easy in 4.0, much more difficult in 4.2). No ranged weapon dropped in our T11 raids until at least a month after 4.1 was released, because the other hunter had also tried ZG every day for a few weeks before she finally got the crossbow from Valiona.

As for the loot system our raid uses, it's basically set to group loot, roll Need if you need it and pass otherwise. It works well because we have to shard at least half the loot after the first month anyway.