What do you think is the all around greatest class to bot with? I have a feeling Druid to simplicity and versatility, not sure on the race.
Stay away from warriors. Race really doesn't matter in the long run. It used to be Warlocks were the best because you could still grind with all your gear broken but the profiles have gotten so good that they will repair now. In general casters are easier. Casters that can heal are the easiest. With that said I guess Shadow Priest would be super easy followed by Balance Druid. Affliction Warlocks are still fantastic, have pet tank and dot-em-up (I prefer Affliction over Destro because if the mob tries to run the dots will kill it off and make leveling easier) and in the same breath Beast Mastery hunters are still very easy as well. Bot the class you want. If you want to play Warrior make sure the bot uses food, it is the slowest class to bot.
I always found shamans incredibly easy to bot thanks to their ghost wolf, ranged casting and healing ability. Also totems like earth elemental to help out if things get a bit difficult. Overall though it would have to be a hunter. Pretty much any class is decent to both with now a days. If you want a race purely for botting, it's handy to select something 'small'. If your a race like the Tauren you often get stuck in doorways etc if your using a mount.
In my experience, Feral druids are the dominant class, next to hunters. On top of that, go worgen for the decreased skinning time. I have 6 worgen ferals, and 1 worgen hunter in case the profile needs to be a ranged. Ferals never die cause they can keep healing themselves, and hunters never get attacked with md glyphed.
Rogue because Burst of Speed. Gotta go fast. Best? Probably not but it's what I like. Druid + Hunter are probably best.
Worgen Druid, but i've had issues with quest botting worgen races so if it doesn't work for you just go night elf druid Most efficient timing for dungeon botting can gather herbs whilst in flight form Worgen speed increase and skinning increase