I'm making a party of 4 Summoners right now, which should be pretty interesting. I'm also taking a gamble and picking Glass Cannon on my main character.
In combat, for getting a side-surface, 2 AP is over-costed for a random and tiny surface.
Your point about the AP cost is fair. I think Dimensional Bolt could probably go down to a 1 AP cost. That would make it more flexible, letting you place a surface and then either a totem or an incarnate.
Bolt has a non-intuitive and narrow use-case, but that doesn't make it a good ability.
In combat, for actually hitting an enemy, it is unreliable and weak.
Because it is not supposed to be a reliable or strong dealer of direct damage. Remember this is the summoning school.
In my opinion, Bolt is not good even for the narrow purpose of making surfaces. Wands, grenades, elemental arrows, and other surface-creating abilities are good for creating surfaces, because they actually give you the surface you want and do something strong and useful at the same time.
Most of those also generate LARGE surfaces, which you may not always want, as large surfaces are more likely to either hit or interfere with other party members, and have unintended spreading of effects and explosions.
Bolt is good for stunning your party and totems when it randomly creates a stun surface just large enough to connect with your blood pools.
So be careful placing it so you don't do that, just like you would be careful aiming lightning at a spot.
Bolt is good for healing the zombies you're fighting when it picks poison.
So don't shoot it at enemies.
Bolt is good when you want to create a small amount of damage on a target and a surface that may be too small to even fit a Totem/Incarnate into.
So don't shoot it at enemies, but at an empty space. That will make a large enough surface to place things on.
So unless bolt is your only surface-creating ability and you spam it before combat until it finally picks the pool you need, then it's a hard pass.
It sounds to me like you aren't using it properly.
