An amazing job, indeed. I too had to migrate my theme options to the Customizer, which in itself posed quite anumber of issues.

Still, in hindsight it was worth it. The customizer is more standarized, and overall a better way of lumping every styling option in one single place. It's not the perfect tool and it still needs some refinement, but definitely a step in the right direction.

That being said... I am not a fan of humongous option pages. I think 600 is way too much, even for a multipurpose-class theme. While users should be able to have their way with a theme, so many options can end hurting them in the process.

I say this coming from a web consulting background, and many people want to have total control-- problem is, it's not what they actually *need*. I'd rather have a theme that enforces some designer-level best practices rather than let users end up with a broken design.