I think even Johns realized that he hadn't created anything special with Simon, which is why he created Jessica so soon afterwards. Even his attempt to team them up in Green Lanterns during Rebirth only succeeded in raising her profile.
I don't have any strong feelings one way or the other about Simon, which is kinda the problem. I've read enough of his comics, but the only impression I've got of him is that he's too similar to Guy, but not as interesting as Guy either. I thought someone would have fleshed him out in some interesting way, but without the great hook that Jessica's got, he just doesn't have anything compelling about him beyond the Guantanamo Bay stuff which doesn't have much staying power.