It's quickish, and ignores mass displacement, so you can make pirate ships without engine centralization, or, you can eliminate RCS for docking. (watch your particle amount though!) Edit: (@ below): good point
Inafune's departure didn't particularly cause the cancellation of MML3 or Rock Man Online, but it did paralyze the franchise (even Mega Man's music composer went with) Though I wonder if someone might ever make some Busters/Buster Sub-chips for BDArmory (inline and radial) to some-what compliment the GN drive. (I know, MS weapons compliment better)