Quote: At over £1000 they should all be "good ones".
You really need to get over to lensrentals.com and read up on this. You're just not reflecting reality here.
From the DxO reviews it sounds like the Sigma 35 1.4 might be the latest thing since sliced bread, and i wouldn't be surprised if it kicked the 31's butt, because it kicked every lens's butts including a lot of glass that cost thousands more than it does from Ziess, Nikon Canon etc., it doesn't matter who you're talking about, it's DxOs top rated lens on just about every system...but that still doesn't mean some won't prefer the 31... rendering is more than just sharpness and pixel peeping doesn't always predict which are the most pleasing images. personally, I like a lens I can carry, along with the rest of my camera bag. You can't shoot with it if it's not there because it's too heavy.
Quote: But wide open. No, definitely not good.
OK, so the question becomes, why can't you just not use it 5.6? Why does it have to be good wide open? And where are the images taken with your better lenses for comparison? You are talking about characteristics that are evident form the photo zone review and that have been known forever, the part you seem to refuse to discuss would be how good the lens is at ƒ5.6 and ƒ8 which for many of us would make the lens worth buying just on it's own.
You're opinion is that the lens should be good over it's while range. But in my world what you seek is excellence... and if a lens gives you the performance at one F-stop or two, and it's an ƒ-stop that you prefer in it's shooting style, you're better off with that lens than with a lens that is better at every ƒ-top, except the ones you shoot at.
A lens that excels in doing what I want, is better at least for me, than a lens that does everything really well, but doesn't excel in the areas I want it to.