I'm still sore about Reader too. Fortunately Inoreader is about as good.
I'm surprised thumbing things down isn't helping you - it was the thing that fixed YTM for me. I wasn't thumbing things down enough, now anything I don't want to hear again I thumb down, and I mostly listen to the personalized and discovery mixes. You might need to switch/reload stations for it to take effect. And IIRC the discovery mix only updates on Wed.