This sounds good me but what if the end users want to use different images?
Of course she has then to use something else than smallImageUrl in the "productDetailId" div, but that's possible. With your solution this possibility dissapears.
Please note that the OOTB UI is mostly for demonstration purpose and is intented to be adapted by users for their need. It's more a template in a way...
What others think about that before I close as "Won't Fix"?