Do not ever listen to Ken Rockwell. Some of his advice is right kind of like I can get piss in the toilet blindfolded.
What is your budget? Nikon's 18-35 is a great option on a budget. Nikon's 16-35 VR is fairly good. Tamron's 15-30 is amazing, but there is added cost, weight, and size if you need filers.
My problem is I want it all... My budget is under 800 and preferably I'd like something that accepts filters and goes from at least 20-35mm. I initially went with the 20-35 2.8 because it fulfilled all of this and is metal; now I'm thinking about other options that are good build quality and relatively fast.
I'm mainly concerned about getting the maximum IQ stopped down and having a decent range that my 50 1.4 can step to without a huge jump
Buying a lens because it is made of metal is kind of like putting a spoiler on your car to keep it on the road. Do you really need a metal lens? The Nikon 20-35 is a very old lens and is likely a very bad choice... unless if you need glasses and don't wear any. Metal doesn't make the glass any better, and it doesn't equate to longevity necessarily.
Reading your last sentence, I would like to slow you down: Don't view purchasing lenses as filling gaps. There is a wrong way to view focal lengths; that is, viewing every focal length as something you need to fill in order to be able to get 'the shot'. If you view photography from that end, you'll be carrying around 6 prime lenses and a zoom, and you won't know what to do with yourself. Or, you just won't know what lens you want to have on your camera. OORRRRR, you'll end up purchasing a superzoom. With that all said, there is merit to being able to shoot at 35mm, 50mm, ultrawide, 24mm, etc.
Shooting at 35mm at f5.6-f22, and shooting at 35mm at f1.8-f2.8, are two very different things. If you're looking primarily to do landscape photography, or you simply like shooting stopped down, then this won't be much of an issue (unless if you also like starscape photography).
With your budget in mind, I would like to hear about what you want to use the lens for? What types of photography? Again, I would say that the Nikon 18-35 is your best bet in your price range, and is a great lens.