Since I'm sure most of the people participating in the conversation are either summoner or blackmage, I'll throw in my unbiased two cents (as a dragoon).

What's wrong with blackmage have superior AOE potential? It's good to have certain jobs that excel in specific areas. Monk has a higher sustained dps than dragoon, but it comes with the drawback of a lot of movement and a short amount of leeway when it comes to keeping Greased Lightning up. Paladin takes a lot less damage than Warrior, but Warrior does more damage itself. Given Warrior is definitely in need a buff, but the idea is there. Whitemage has more raw healing and Scholar has some damage reduction buffs. Each job is supposed to have a unique feel and a semi-unique position in a party.

But... I do agree with people that Summoner should be more about its avatars and less about the caster. It's such a cool job, not to mention a major staple of the brand, and could be a lot more flashy in it's abilities rather than a dot whore.