Frankly, I don't think anything is set in stone... It's entirely possible that they came up with scholar as yet another mage job, and realized books made way more sense for that than for arcanist/summoner, and honestly since arcanist uses carby and summoner uses summons they may have something else that isn't natively a weapon (like stones or gems.). A very curious picture indeed. The background is very hard to pinpoint (except the guy in harvester gear.) since it just seems to be various people in non-job specific gear.

It's also entirely possible that it's just a massive troll on akihido yoshida's part. Or that they snuck in arcanist with some special new non-summoner gear to mess with our heads.

We can speculate as much as we want, but until we get official word... or the game actually launches... nothing is really off the table.