I definitely agree with your foot shape dictating the correct fit. For me the Kenetrek relief came in the form of better leather, and most importantly a more structured (stiffer) sole. I've dealt with plantar fasciatis off and on for a few years now. Even with orthotics I could only get temporary relief from the pain. I used to wear softer soled boots and even my heavier duty boots were softer in comparison. I was actually working at an outdoors store helping a customer with a pair of wading boots, they (husband and wife) both had some interesting hiking boots on and were very particular about footwear. I spent 3 hours with them making sure the husband got the perfect pair he needed, but they also schooled me up about the wonders of Italian made leather boots, as well as a stiffer sole. I decided that it was worth a try as with the softer boots I've always worn, did nothing to help my feet, probably hurting them more than anything. Obviously there's other factors involved with foot overuse pains etc, but stiff the boots are the only true change. I got a pair of Desert Guides from Kenetrek. I took my time breaking them in and laced them consistently. No more pain. I even started a job where I was standing for 12 + hours each day on hard surfaces, and these worked like a dream. I also use them to hike 10 or more miles in very uneven mountain terrain, with no sense that my boots count handle it. I'm pretty hard on my gear, and don't like to ever feel under prepared. I have yet to get the Mountain Guides that have a similar sole but with more height and some insulation options. I've actually served in the USMC in multiple Infantry combat deployments, and I wish I had access to these when I was in. I really can't say enough great things about them.
Sorry to ramble, I'm just very passionate about them.