i play druid and my friend plays warrior. we level together
are we a good duo to kill pre BC bosses to get good loot?

I regularly run my level 85s solo through any dungeon level 75 or lower that I can find. I am usually successful. I have a warrior, a mage, and a hunter. It's not that difficult, and no, you don't have to be a druid.

I auction any gear I find that isn't BoP, and whatever is BoP I either disenchant or just sell it to a vendor.