I thought Quake II’s engine was better than GoldSrc since GoldSrc was an Updated Q1 engine.
Then again Quake II is also an updated Q1 engine, and source still retains much of the original Q1 engine pieces so, maybe not.
I’ll bet ID will find a way to reverse buy Bethesda and force them to use ID Tech 1 (ALA DooM) 
Yeah, but its really heavily updated. And more importantly later, so they could have incorporated Q2 improvements. Not that it really matters.
I don’t hate Gamebryo, but I do hate that all of Bethesda’s games tend to run badly for a few patches on the engine. If they used id tech 5, they could more easily call up someone who knows what the fuck they’re doing and fix it. (though with the amount of small bugs that they let slip typically, I doubt John Carmack would be pleased)
Darkplaces.
Actually, that might end up looking better than gamebryo with a few modifications 
Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.