the thing is if you bad as warrior you can still win easy.lucky mace stun + few crits = win.there is almost no skill requirement to start doing arena as warrior and do fine.
as ret tho you need to have way better understanding of your class,its way way harder to get good results if you are not very good at the class.mostly thats the reason so many people say ret sucks.
just think how much ret have to keep in mind in arena game.he have to time all his blessings,rebuffing all the time,doing dmg,time well offensive cds ( since wings dont let you use babble for 1 min it can **** you up so easy),heal when needed,manage your mana,CC.its just so much to do how can anyone say ret is low skill class in PVP?