ClickToPlugin works like a charm on Safari (and it removes all video ads as a side effect). I'm not in any way affiliated with the developer of ClickToPlugin,

ClickToPlugin works like a charm on Safari (and it removes all video ads as a side effect). I'm not in any way affiliated with the developer of ClickToPlugin, I've just been using it to the effect described by OP for some time and it's the only thing that's been keeping me on Safari for a while.