I did hardcore raiding on retail in wotlk and if you want my advice go MM = win. BM was ok but ARP was too overpowered back then so MM was the king of dps in pve when it comes to hunters.
If you wanna try MM,
Get as much ARP as you can, I had 100% arp in HC gear then, wolf pet for crit, and MM rotation is quite simple that is why it was best in wotlk,
rotation is rapid fire > Serpent Sting > Chimera > Aimed > Steady spam rinse and repeat, don't even think of using arcane shot cause its a waste of time and mana, you do more dmg with 1 steady then 1 arcane and since steady should be on 1.5sec cast with enough haste, it makes it the same as arcane cast since GCD is 1.5sec.