I think weight distribution is somewhat subjective:
I run the panniers up front with sleeping bag, pad and tarp tent on rear rack (shown on the left). Another guy runs rear panniers with sleeping bag on the bars... and we've got a whacko in the group with frame and seat bags and a handlebar sling.
I'm not a good technical rider... the guy who runs the rear panniers is a expert rider and likes his setup.... he cleans obstacles with that rig that I could never clean, regardless of load or any other variable you could come up with.
I like front panniers because they damp down the bounciness of riding a rigid fork and that the bike is more balanced for portaging.
I don't think any of us are concerned about over stressing wheels.... I run cheap wheelsets (<$150) and can't attribute any wheel issues to additional weight of touring.