I am aware of Earth's other Green Lanterns, thank you. Kudos for spelling "Rayner" correctly, you'd be surprised how many utterances of "Rainer" and "Raynor" you see out there.
My point was that Hal was created in 1959 and since then, he's headlined three of four volumes of Green Lantern (vols. 1, 2 and 4; volume 3 was Kyle's title after issue #50), he's been a founding member of the JLA three times over (pre-Crisis, post-Crisis, post-Infinite Crisis). This here:
http://dc.wikia.com/wiki/Category:Green_Lantern_(Hal_Jordan)/Appearances
--is a list of just about every appearance Hal's ever made in a DC comic book, from Green Lantern and Justice League of America all the way down to stuff like Day of Judgment and Justice League Europe. You can tell just by looking that it's well over 800 entries long. Again, I don't see how the character's been underexposed or underdeveloped.
And as for Hal's character itself, it has been developed. Being brought back from the dead - being dead in the first place because he murdered the Corps and the Guardians and then gave his life to reignite the sun - will change a guy, and it has. Hal's still plenty confident, but he's not the supremely arrogant SOB he once was. His reverence for the ring and the Corps is much greater - he's seen exactly what goes in to both of them and he knows what the universe was like when there was no Corps patrolling it. In the pages of GL right now, Johns is ever so slowly starting to re-explore the relationship between Hal and Carol. There was clearly love there during Blackest Night, but as the point man for the Green Lantern Corps and the new Queen of the Star Sapphires respectively, it's not that easy.
It seems to me sometimes like he was just resurrected yesterday, but Rebirth happened over five years ago and GL vol. 4 is up to 59 issues already. Hal's been given plenty to do since then and it all shows.