I haven't played since December, but at least I can read (and comprehend) the damn forum rules.
Never mind that the expansion is still being worked on, and is in flux. Never mind that the answer to your question won't be settled until the sims are complete and people get some parses once it goes live (and will likely be analyzed and published on this site then). You're asking people not only to do your research for you (hint: if the question you asked had an answer, you could find it just by reading the thread) but also to get out their crystal balls and tell you what it will be like in 2-months-plus.
This isn't a help desk or a handholding forum - the Homerian litany of posts that end up in the trash heap, plus our forum rules, evidence and elucidate that quite amply. You've had an account here 2+ years and haven't figured out what kind of posts get infracted versus those that don't? Come on now.
I have not played in a year. If I start up again with the new expansion, what spec should I use? Any particular plan I should start doing to be a good raid member for my guild?