But in the end you're right: Don't use a lens when it does not perform.
Now you're just putting words in my mouth
I was saying, use the right lens for the right job, and if you do only have that lens at hand, then take appropriate measures to eliminate/reduce it's flaws. I.e stopping down
As far as your argument about using dof goes, you're using it on DX, so you're getting larger dof anyway. That and are you really
getting that much different a look shooting at f1.8 as opposed to 2.5 or 2.8? I mean, it's a choice you have to make. Either shoot wide open, and bear the fringing and ca, or stop down. It's not as black and white as you seem to think it is.
Oh and here's a shot, wide open. Yeah it's web res, but seeing as that's what you were posting earlier;
I suppose it's just a case of your shooting 'style', being very different from everyone that is able to live with this lens.
Here's another one, this time at f2.2;
Sure you can see some green and purple CA in the frame of the window if you look hard enough. Does that automatically make the shot garbage? Not to me. Opinions may differ obviously.