1. Nicholas fell on top of Glenn. It could have been his guts being eaten.
2. Usually you see blood coming from the mouth of the victim being eaten. No such thing with Glenn.
3. There is a space under the dumpster that Glenn could crawl into.
4. He wasn’t eulogized on The Talking Dead.
5. He wasn’t a guest on The Talking Dead like every other major character that has been killed.
6. Statements from the producers are intentionally vague.
He’s not dead yet.
The why would he be screaming with his face contorted in pain?
"Usually you see blood coming from the mouth of the victim being eaten. No such thing with Glenn."
Sometimes you see blood from the mouth, sometimes you don't. That was case even with other victims in this same episode.
"There is a space under the dumpster that Glenn could crawl into."
And the zombies would just crawl under right after him like they always do when someone tries to crawl under something, like a car.
"He wasn’t eulogized on The Talking Dead."
He was in a sort of way. At the end of the eulogy the words to the effect of "Please don't let it be true" were flashed over and over.
"He wasn’t a guest on The Talking Dead like every other major character that has been killed."
And the show itself said you shouldn't read anything into that. If they try to pull off some dumb deus ex machina to "save" him from an inescapable situation it will definitely cheapen the show.
Next week's TD has a cast member on the couch.