Elenarie: It was a complete piece of shit. Raiding has never been better than now.
Matewis: What was wrong with it compared to now?
Back in the olden days:
1. When you die in a instance, you release spirit in the only graveyard in the zone where the raid is and usually these are FAR away where the instance is. And in the case of certain raids like Blackwing lair, you had to go through the dungeon prior to blackwing lair case in point Upper Blackrock Spire. Which is why they added a thing that teleports you directly to blackwing lair's entracne.
2. Not all class specilizations were viable for raiding. The Protection Warrior was the only viable tank (A class made to get the attention of all the monsters/enemies), Priest were the only viable healers, and many other specs for Damage Dealers were completely worthless save for a select few.
3. In the time of vanilla WOW it can take FOREVER took invite and organize a group of 40 people because some of the raids were MADE for 40 people, realistically 25 can do it but the raids are so hard that you needed the extra 15 people to tag along. But this did made joining Guilds all the more viable.
4. Attunment quest, you cannot access the raid unless you have done the attunment quest that unlocks and leads you to the raid, so not only do you need 40 people, you also need all of them to unlock the raid themselves, each and everyone of them had to do this.
5. The raids themselves were very experimental at times because this was Blizzard's first time doing an MMORPG making content like this. There are horror stories of bosses that are so bullshit its insane.
-A Red Dragon in Blackwing Lair killed some many groups because of his "Death Debuff" that he was nicknamed "The Guild-Breaker"
-The final boss in the Temple of Ahn'Qiraj, C'thun, was never beaten until he was nerfed/made easier.
-The Four Horseman boss in the undead floating fortress called Naxrammas required 8 Tanks when mostly you just needed 2 combined with the fact that Warriors are the only viable tanks and you can see why this boss was so hated and infamous.
And raiding was still bullshit like this up to Burning Crusade I have heard stories have how broken the BC raids were, they were getting patched on a daily basis.
Wrath of the Lich King was perhaps the time when raiding was finally perfected.