Raise any safety issues with your ops department and get them to action it. I know exactly where you are coming from and it irks me that some fellow controllers seem to have no idea about aircraft performance. Controllers should know any restriction required in their airspace and advise you guys in plenty of time. Whilst "descend when ready" might not always be appropriate,you must be able to apply relevant restrictions in your airspace. As a trainee you have an excuse, but as a valid controller or an instructor, you do not. I accept that weather can play havoc with restrictions but it is not rocket science. I heard of a controller ask a B747 to reduce speed to mach .73 last week, I mean, come on!!! The competent amongst us will always strive to do our best to assist, unfortunately I cannot speak for all controllers. Stay safe guys and don't taint us all with the same brush.
