For single target with appropriate traits:
For sustained multitarget with the Cleave talent the stat ranking would be:
Since mastery is such a bad single target stat you might still prefer going haste for M+.
If you go for a setup with Warbreaker for burst AoE, the stat prio will likely change a lot with different azerites and kill timers, most of the time favouring Critical Strike.
Crit: gives a chance for your attacks to do double damage and your Auto Attacks that crit give 30% more rage.
Versatility: increases the damage you do and reduces the damage you take.
Multi target situations tend to favor Mastery more, although it depends a lot on the situation.
The best way to calculate stat priorities for your character is to "sim" your characterFind out how to sim
All of the races are close in DPS, but if you want the absolute best then go Troll for Horde and Gnome for Alliance.
Gale-Force Striking is usually the best option for Arms.
When it comes to ring enchants just go for what sims best for you.
When it comes to gems just go for what sims best for you.
Flask: Greater flask of the Undertow.
Food: Baked Port Tato.
Health Potion: Abyssal Healing Potion.
Rune: Battle-Scarred Augment Rune.