GWs meta changes over the past year

Well, I have had a long break from GWs but have been toying with the idea to pick up my characters again and head into the fray. However I am slightly put off by the amount the meta-game might have changed since I last played. Would I have to relearn everything I thought I knew about what works, what doesn't and all the little ins and outs? For PvP and alliance battles would I be able to have any success with the kind of pvp knowledge and skills that were effective a year ago?

thanks for the help. http://www.theamazonbasin.com/gw/forums/index.php?showtopic=9310