Summons are very overpowered in this game right now. With just 1 point in Geo you get a spider that automatically scales in power regardless of Int and soaks up thousands of damage every fight. Any character can get that.
Then there are the focused high Int casters with their reduced cooldowns who can spam endless amounts of summons on the field.
And the AI is terrible with this - you can have an elemental tank enemies with pure elemental damage that will continue to gang up on your summon and heal it for its entire duration. After which you just drop another one on them.
It's a fun game but it is actually full of overpowered stuff like that. Heal spells are another example of overpowered stuff. Can't really do anything without them, and with them vitality loss becomes rather meaningless.
Hybrid builds are also impossible to pull off at the moment. Attribute scores need a curve in their cost like abilities so you can have a more even spread for a hybrid build at the same cost of focusing on your main attribute. Right now the only viable build is to focus on one or two attributes.
But as far as the topic goes, the summons make any kind of tank PC obsolete.
