I play on Geforce Now, where the GPU is top notch but the CPU is conparatively weak. With DX11 there is a very significant framerate gain, as in I can almost max all settings (other than model number in pve metas). So even with the current implementation of DX11 (setting aside a few bugs and rare crashes) the situation of “you need the most expensive CPU” is clearly changing.
I'm not saying you need an expensive card, I'm saying in your price range taking some cores over a single-threaded cpu, especially mid-to-high end, is likely a good option.