I do like many things, but badly designed things I don't like. Blurring an image is not quite what I understand under making it blend into the interface. You have not yet so much experience, so I don't want to reproach you here
But imagine your slider in the interface, you cannot blur the right end of the slider when its not full technically so it would look ugly on the right edge.
Compare:
Also the things you put into the interface have no consistent design, stars are pixelart, rest is images, some are taken from windows media player etc.
You have to take into account that VLC runs on many Systems with totally different visual styles. So VLC has to integrate itself best into all of them. It takes quite some work to figure out a compromise that pleases everybody.
Just some points you might think about