I agree that early game (level 3 in this case) 10 points in summoning is really strong. I thought that summons kept getting stronger as you level up even though you don't put point in summoning since they scale with character level and summoning level. Since a non lone wolf character is maxed at 10 in that skill, I assume that they can use their summons at end game with some efficiency, if not everyone would pass up on the skill.
I'm still torn between pushing it to 20 or investing in other skills to start dealing damage myself.