It is funny that the truth about BC is finally being discussed honestly. Indeed, he is an excellent technician, but aside from the modularity stuff his work is of narrow interest and lacks exciting ideas. People are very respectful of him, but you can't say with a straight face that he's been influential.
Gabber is both technically amazing and full of original ideas: his proof of purity for intersection cohomology, and his work on local uniformization and finiteness theorems for etale cohomology of excellent schemes, are both incredible achievements, just to pick two off the top of my head.
Agree that Gabber is at a different level in both technical prowess and originality. One of the reasons that the field of algebraic number theory has been going strong is that there are top talents like OG who are willing to use their precious time to provide "check and balance" on important works.
Speaking of check and balance, it's somewhat ironic that Conrad, with his outward reputation, turned a blind eye on his own students (Masullo, possibly others).
Gabber is now over 60. It's interesting to ask if there're any worthy successors of his among the younger generation. Perhaps TK comes close?