I'm a returning player wich will mostly play casually,i'm thinking about starting with a class that i have never touched, wich are dk and priest, i would like to know wich do you believe is more fun, and i know that the concept of "fun" depends on tastes, so it would be nice if you could share your toughts, what i was thinking is one spec for pve and one for pvp (still casually so probably pug/bgs) dk would probably be tank in pve, with priest im not sure between shadow and discipline for pve, pvp would mostly like to try disc since it looks fun on paper.
sorry for making it long, will await for some suggestions, thanks everyone!
Entirely depends on playstyle and what you want to be able to do.
DK is a lot more self sufficient. Once you learn the ways, you can solo hc dungeons. Skilled Tanks are also in higher demand than healers.
Priest are great as well. Not suited as much for solo content and despite it's power, is usually the least used healer in raids due to it being so versatile that it just seems to complicated for some, and for others they don't really get a grasp on how to use one to it's max potential. Holy and disc are both viable raid heals.
PvP, if soloing you'll want either unholy (blood works too, but not as much against casters) or shadow priest (disc if you have a good high dps output partner)