So, this Friday I'm going to preorder Legion, and wondering what should I boost to 100, I've been rolling Shaman since like forever, and would like a breath of fresh air.
Was thinking about rolling Paladin, or Warrior, just to switch things up a bit. The only thing I don't really know, witch of the classes mentioned are "future proof" by that I mean witch is the most reliable to be good in PVE/PVP in Legion when the patch hits.
I watched some videos regarding the specs of the two classes, and what really stood out to me was the Holy/DPS spec for the Pally also known as "Shockadin".
Looks like a pretty nice spec to mess around with in PVP and gives a nice fresh approach to playing WoW (at least for me), and thinking of going Retribution DPS for Raid Encounters.
I've played Warrior a bit, but didn't get a strong grip on the class, so decided to go back to my Shaman.
I don't think that anyone here can give you an answer to this right now.
Legion is only in Alpha. To give you a answer you should wait till release of Legion.
Your pre order boost isn't going vanish till then anyway.
I think PVP wise, warrior is a very safe bet. It's also a pretty fun class. I'm leveling mine as Prot in dungeons, and it's a hoot. So many abilities. I leveled a tanking druid the same way before, and a warrior just feels like superman in comparison.