Potent Magic makes the Arcanist, by default, the best SoS caster in the game, bar none. Counterspelling makes him the best against the scariest bad guys in the game, other casters. If Dimensional Slide can be used to escape grappling, which may well be the case (we'll wait for an FAQ on that one), the Arcanist is second only to the Teleport School Conjurer in terms of defensive/tactical movement ability, and the gap between him and 3rd place is huge. And that's just for starters.
The "few things" the class does better are quite potent, indeed.
First off, I want to apologize to you for becoming rude and snippy. It was 3am, you offended some of my sensibilities and I went on a warpath. Sorry about that. >_<
When I heard you wanting to ban the Arcanist from your games, I took the position of a whiny player caterwauling to his GM about losing his favorite toy. As I mentioned in my OP, I can't wait to play the Arcanist. Having played many a Wizard and Sorcerer and having seen someone else play an Arcanist I understood the weaknesses of this shiny new class, but want to embrace it all the same, because, as you've well noticed, it has some cool abilities. Do I think the class and its abilities are powerful? Well, yes. Do I think its powerful in such a way that it diminishes fun for surrounding players? Not so much.
I just don't see the Arcanist as a problem class. I would love seeing it at my table. It gives me nowhere near as much grief as other things I've encountered: Magus nova one-shotting bosses. Fey Kitsune Sorcerer spamming confusion, making the whole party wait while the monsters very slowly and boringly kill themselves. Crane Style users, before that was nerfed. An Oracle of Life altogether removing the fear of taking damage. Druid clogging up the battlefield with Animal Companion, Summons, and Cohort (Might reconsider my policy on Leadership for my next campaign) and bringing combat to a crawl. There's just so much out there that makes me grimace as a GM, it's hard to see why you singled out the Arcanist as the enemy of fun.
If some particularly feature of the Arcanist is just too destabilizing, perhaps just nerf one particular exploit. I just hate to see the death of a cool class.