You should *never* disable V-Sync in Creation Engine games. The game logic and physics are tied to the FPS. After playing a while with faster or slower framerate the NPC's schedules shift out of place.
I'm with you on the vsync. I thought it would be cool to run around at over 200 fps and then I saw what happens lol. It's reminiscent of those comedy skits that play in fast forward with some benny hill theme playing.
Anyway, the most relevant information for these benchmarks is the minimum fps, and that's not included.
The performance of the game also is dynamic just like the game world. Early in the Main Quest, the world isn't as dynamic as later. There's a lot more going on later. Areas that were previously empty now have NPCs, etc. Enabling Invisibility in the console might also remove CPU calculations for the NPCs like pathing and collision, which would certainly have some impact on performance.
I heard a rumor that Bethesda's Creation Engine license expires with this title. They could certainly license it again for the next titles, if that's the case. Who knows?
As far as Gameworks goes, I'd get used to it. Nvidia has something like 80% of the AIB market, and it seems like a lot developers don't want to hire more people to code their own solutions, so it might be around for awhile. Let's hope it gets better.