MC wasn't really hard even back then.. maybe Ragnaros caused some issues but thats about it.
We basically did first guild run up to 3rd boss with 28 people.
BWL did have some hard encounters like Vael which took some time to get the DPS and healing requirements. After that we pretty much one shotted all bosses up to Chromaggus and Nefa. Nefa took like 2 resets.
AQ40 was on a different league starting from Huhuran.
Classic raiding is more like social gathering, having fun and looting epics while killing bosses rather than some sort of sports event.