I am tending to be skeptical mainly because I haven't seen photos of the text or stone yet to be able to see the problem areas of the text for myself. I also wonder how sure other scholars are that the text is authentic (not forged or tampered with) and really from the first century BCE. Jim Davila is keeping track of the media attention HERE.
I am very cautious because of what has happened with the James ossuary and the Gospel of Judas. The ossuary is highly suspect as a forgery and the Gospel of Judas was so badly misread.
I think that we need to approach this newest discovery with caution, and sort things out. One of the things that keeps nagging at me is the fact that the early Christians had to explain again and again that the messiah was meant to suffer and die, to Jews who thought otherwise. If the Apocalypse of Gabriel is authentic, then its messianic ideology must not have been very well known among the Jews.
Anyway, I'd like to collect some initial reactions and thoughts about the Apocalypse of Gabriel.