You bought this developer's add-on off your own free will. Nobody held a gun to your head. It was well-publicised that this add-on would in now way be up there with your ' Pee-Emm-Dee-Gee' that you are so fond of trumpeting, and it was sold as such.

It had limitations. If the developer decides, yes there are certain aspects 'we need to look into to improve', I am sure they will or will not. That is their prerogative. You can belly-ache as much as you want to. The final decision is the developer's, not your behest!!