However, personally, I'd like to at least have a wide *variety* of summons that I can choose from to adapt to different situations. I don't need to be able to summon hordes after hordes of monsters. The lack of variety is the one thing that kills the feel of being a *summoner* for me - you summon basically the same thing over and over. Giving him different abilities that are strictly tied to the four elemental schools doesn't quite cut it. I prefer different creatures, with varied appearances and interesting unique abilities that reflect their nature. Of course, they also have increasing overall combat capability to make leveling up as a summoner exciting.
Obviously you can't take points into all those schools, but you can pick a couple if you want variety in summons, and they all get benefit from summoning.