I don’t agree with any of the comments, for instance the handle its self acts as a complete design, and so what if it looks like a “fancy vase”(Jon.dorsett) meant to be used by lawyers, that’ll just bring an increase of value to the product. And the product hasn’t been fully tested in an uncontrolled environment, how does it test against children? What’s the hottest temperature it can withstand? Without it been tested no one can depict this COFFEE CUP as uncomfortable, nor bad design just by the looks of it.
There’s no absolute solution because you really haven’t found a problem with it yet,-as far as read in your post- therefore, not until you test it, and see how much more than just a coffee cup it is, Can one find the solution. By the way, I saw your design, and one question, is the handle in any way have edges? In which that can hurt someone gripping the cup and it’s included weight.