I disagree. I think the strong stripes are business-y enough that they need a softening touch, especially given that it's a hard-finished, lightweight worsted. In a flannel, then I could see a darker tie.
Sugarbutch has it right about the cut of O/O's clothes, but Ianiceman has it right about the ludicrous casual stuff he'd post.
Gmm, I think it's a venal sin to go sockless with that navy blazer rig. I think it's a bit vulgar to go sockless in wool trousers (I think I stole that idea from John Tinseth, though maybe not), but it's a rule that has stood me in good stead.
So, the idea of "softening" a business suit doesn't really compute, as far as I'm concerned. As I see it, a business suit calls for business accessories, and a casual suit calls for casual accessories. There's a spectrum, to be sure, but pin stripes fall squarely on the business end--particularly, as you point out, with a worsted, non-flannel. I'm probably a little more rigid about these things though...