That was why I liked most of Johns' earlier work. He took the time to build a supporting cast, and that is the biggest weakness of Green Lantern right now. Whatever happened to his brother Jim and the rest of the family? We got an appearance in Blackest Night eighteen years ago but that's it and I'm disappointed. The definitive moment in "Sinestro Corps" was when Hal told his family to leave Coast City in GL #25 and his response was "Hell no!" Don't get me wrong, the book is doing fine right now but I am somewhat unsatisfied that we get the New Guardians for a supporting cast but Larfreeze and Sinestro aside, I'm not warming up to them a whole lot. Plus there's the fact that Hal rejoined the USAF at the beginning of the title, he's been AWOL a lot and I don't think he has that much leeway with his commanding officer. There are so many things that Johns has forgotten to address since he introduced us to the various Corps.
Come to think about it, what happened to Hector Hammond? Did Krona just remove the entity and toss him in a ditch? What about Hal's other foes? I remember there being mention of Evil Star from Blue Lantern, Sister Mercy a while back, and then there's Sonar who we haven't seen since about #4 or #5. I thought we would have seen something with him a while back.
So much missed potential. 
Nonsense. Hal's family already proved their bravery & such in The Sinestro Corps War, and they are currently living a somewhat normal life, whereas Hal's life right now is kinda nuts, what with having to work with mortal enemies, and one with whom he's trying to figure out things with, and he's probably stressed. Why do you think Superman asked Hal when the last time he's taken off the ring? Also, your problem seems to be not that he's not building a supporting cast, but just that he did and you don't quite like them right now. He's actually built Hal quite an amazing supporting cast, one that has a lot of potential to be more than just secondary characters.
And I'm sure he'll get to Hector Hammond at some point, as well as other villains. Just be patient.