Just finished a run with a summoner and thought i would share a few impressions and ideas on the class.

Love the concept of the class. Having a single summon to buff and control makes the class stand out from the crowd, and the summon itself kinda becomes a 5th party member.
Not a fan of the appearance of the summoned entity, as it sort of just looks like a mini elemental.
What i would love is having the creature start out as it is, and then grow and change as you gain levels, eventually turning into a chutulu esque whirlwind of teeth and tentacles.

The biggest problem with the class are the totems.
They do little damage, die from any aoe, attack random npcs and worst of all they do splash damage which damages friendlies and also set off random fields.
There are already too many ways to accidentally trigger a field, and we really do not need an uncontrollable one via totems.
It also takes 4 entire rounds to get all your totems up, at which point most of the previous ones will probably have been destroyed, and most fights will be close to ending anyway.
I found that there are usually much better uses for those ap points, and wound up ignoring totems most of the time.

Perhaps it would be better to only allow 1x totem up, and buff its hp/dmg/cd, or rework totems to instead buff or debuff in an aoe pulse.
Since the class is centered around the incarnate, totems could also be reworked to affect it. Like allowing it to teleport between totems, or perhaps be healed/buffed by them.

Anyway, just some random thoughts i had after playing the class.