[Gimp-developer] Why can't we alter a filter-setting after processing...without recalling this filter?

[shepherdsbush post com]

Dear developers,
I want to point on a general weakness of Gimp!
I never understood, why filter-windows have only the buttons "OK" and "Cancel"!
If you use a filter, and you are satisfied with what you see on the little preview, you click "OK" and then 
you see on the big picture, that it's not satisfying. So you have to recall the filter again and make a 
better setting....and so on!
Wouldn't it be nice, to use a filter, find a setting, and if you see then after processing on the big 
picture, that the filter-setting could be improved, you alter this setting a little bit And then after you 
found the optimal setting....then you click OK.

1. Is it possible to implement this soon? Maybe a third button "stay a little while" :)
2. Why haven't this major feature implemented for so many years?
3. Is this for the developers a very complicated thing?

Thank you for this great program....and sorry for my probably bad english. 

Kind Regards

Thomas