According to my personal scale expert (aka Jesse), the Hero Series X-Wing is actually pretty close to perfect scale match for the 3.75" figures -
29 Inches long on this ship means it's actually 1/17 scale, almost on the nose. Star Wars figures range anywhere from 1/17 to 1/20 (the newer more lean to 1/20).
I'd say he's right. I put some action figures out with this thing (my son got it for his birthday), and they look close. WAY to small to be 6" scale.
Part of me wonders what a 2.5" scale line would look like with ships made to accurate scale. That BMF (while awesome) is still under-scaled, though not as bad as the 78 version. BUT, if they made a Falcon that size-ish with smaller figures, they could probably hit the point. But then I think how many would be let down if they didn't get that BMF (with rectangular deflector) at 3.75" scale. Maybe a line limited in scope? I loved the M.A.S.K. figures back in the day, and I appreciate now that the smaller scale of the person allowed them to create better vehicles for those plastic men to ride in.
For vehicle lovers, the 3.75" scale hurts getting accurate scaling.