The CharOp guys have a much better grasp of, and feel for, the rules than practically any WotC developer and especially any editor.
I don't think that's necessarily true. As is often the case with developers in any industry, they get used to seeing things from a certain perspective, which is often the "intended" perspective.
As Rodney Thompson sagely said, "No game system survives contact with its player base." What this means is that once the players get their hands on the system, regardless of whether it's d20, GURPs, Palladium, or what-have-you, they are going to come up with and/or find all sorts of problematic combinations that the designers never really considered simply because it was outside of the intention of how the rules were written.
So the developers probably have a pretty darn good idea of how the rules are supposed to work, it's just they've been so close to the material for so long that they've just gotten used to seeing things a certain way. Happens in writing just as frequently, as an author frequently makes for a notoriously bad editor when it comes to editing their own material. The author
knows what was intended, and so may mentally "fill in the gaps" when doing any proofreading or editing.
As for the editors knowing the rules... who knows? I'm sure there are some that know the rules just as well as the CharOp guys, some that barely know the rules at all, with most falling somewhere in between.