Oh, Moose. Those pictures aren't new, and that armor is definitely not the new, special CSE. CNJ is wearing the Vanya Robe, for one (and it's true that WHM can't wear it, but THM can). I don't remember the names of the other sets, but the GLA and MRD gear are definitely familiar.
Arcanist isn't shown like that for the same reason Summoner isn't -- they're not ready to release in game renderings of them. I find it sort of surprising that they'd release the concept art for CSE for their new class even before doing so for their older classes. They've been pretty tight-lipped about CSE for the combat classes so far. ...Not that that's really an argument either way, just a thought.
I simply find it hard to believe that they would intentionally get all our hopes up just to be like, "LOL THERE'S NOTHING HERE, WASN'T THAT A FUNNY JOKE, GUYS?" And whether or not you think SCH is really coming, it's definitely obvious that they're teasing us about it.
We KNOW we're getting new jobs in the nearish future, Yoshi-P did mention once that he'd like to add more mages before putting in more DoWs (though he also said he'd like to add a stealthy war job, so who knows where we are on that front). There's also a reason I've been leaning towards there being nine jobs at, or close to, launch. And that's balancing. Each city has three guilds with three combat classes in them except for Limsa, which in v1 had only one class, but all three guilds. With ACN being added, that makes two classes in Limsa and still a third guild not being used. I'd been using this previously to quietly assure myself we'd be seeing a musketeer soon, but with redesigning the cities entirely it wouldn't be difficult to change that guild into one for a different class.
That would also explain the timing of this "leak". They'd need to get it out before Phase 3 when we all start running around Limsa and stumble across an unfamiliar guild.