You never know what a good thing you have until it's (maybe) gone. It certainly looked as if Glenn's luck had finally run out at the end of Thank You. However, his possible death (falling into a horde of zombies after Nick shot himself and knocked Glenn over in the process) has been left as a cliffhanger of sorts since then, not yet revisited. That will change soon, but it has given us chance to reflect on how crucial Glenn has been to the show. He is, as mentioned, the soul of the group. Likely the conscience as well. A good man in bad times, without trying to be too cliche. Heroic, without ever asking to be the hero. If he is dead, hopefully we see a little more of him in flashbacks. If he isn't, cherish him all the more, because at some point, just about everyone on the show will likely have their number called, and exit for good.