I 'carved' a cork into the same shape without those ridges and have been using it for the last couple of years. The simplest, cheapest solution for the Dynavap/Wand combo. Works really well.
Do you think your list are design shortcomings or were done purposely as to stablish 2 different products? -after all The Wand was not initially intended for Dynavaps..
I looked into mine and I can also see a bit of blue cable behind the glass, not as much as your but it is there. I have been using my wand for a couple of yrs now and no issues of melting cables...
If this happened to me, my first contact would be with the manufacturers, they designed and built the IH.
They even have an email address for service queries in the product page. Just sayin.