Here's how revision numbers commonly work. A revision number typically looks like X.Y.Z. X is the version number. A wholly new version number means extensive changes, and often new features. Y is the major revision number. A major revision won't introduce new features, but may include significant changes or fixes to existing features. Z is the minor revision number. This is a small, usually isolated adjustment, tweak, bug fix, or what-have-you. There's no absolute boundary between these. In CPUs, stepping serves a similar role. The stepping relates to updates to the CPU firmware.
I can't speak to whether Gigabyte commonly stays at version 1...but is it 1.0.0? Perhaps not.
Also, and the bigger factor: for the last few years, I don't believe there have been *dramatic* changes in motherboards. With Skylake...there most definitely are. DDR4 is brand new. Higher-speed USB. Same with the Skylake processors; it's got more architectural and functional changes. So the risk of problems is higher.
EDIT: also, there's *serious* marketing pressure to get the boards out. That always involves more risk that the engineers haven't had the time to find all the issues.