I don’t know if anyone has suggested this already, but how about adding an interpolator to Kdenlive’s Transform effect? I’ve seen one in the Corners effect, and I was wondering if the Transform effect (as well as the Position and Zoom effect) could have different interpolators when it comes to utilizing different graphics.
Hi, and welcome to the forum and community.
AFAIK this hasn’t been suggested already, so you are the first one 
While this doesn’t mean that the effect couldn’t be improved by using different interpolation methods, it at least indicates that fore most users the effect delivers acceptable results.
For fringe cases like pixel art there are other scaling filters available.
FYI, Kdenlive doesn’t have its own effects - it relies on what the MLT framework provides which uses avfilter and frei0r libraries for that. So, any request for changes to effects should go to the maintainers of these libraries.