no one can answer that but yourself.
That said though, if you want to raid -
do you have a spot waiting for you
are you going to have to search for a guild and transfer to a new server to do it
even if you have a spot available, will you be welcomed back by the guild you left
will you only be a part time flake that shows up at a new patch and leaves 1 month later after you are bored, if so, stay away, you'll do more harm than good with your current guild. Personally I really hate the people that show up for 1 month after a major patch or expansion and then all they do is qq when they are raiding, then quit again. If you are this type, stay away, find another game.