Does a turntable make a DRAMATIC difference?

Just like in real estate its location,  location, location, in analog its set up, set up, set up.  If its not set up correctly and yes small differences matter, the quality of the equipment will not shine through.  I agree that you need the equipment and know how to do it yourself. Its part of the fun.  If you don't have the patience or desire, best to stick with digital.  Call me sceptical but no one else is going to do it as well as you, assuming that is you know what you're doing.

The only function of a turntable is to rotate your disk at exactly 33 1/3 rpm. I assume you already have low wow, flutter and rumble. If so, how do you think it could further improve the sound?

@rudyb - that is a gross mis-characterisation of the function of a turntable. The best description of the function of a turntable that I have hears is Touraj Moghaddam's statement that it's function is "to measure the groove with respect to time". Anything that interferes with or corrupts that measurement will impact on the accuracy of reproduction - including resonances or sources of noise anywhere within the system or any inccuracies in the temporal component. Eliminating all of those is a non trivial engineering challenge.

Good explanation, @yoyoyaya 

I think the OP should tell us in what respects his digital set-up outperforms his analog. We don't know what to address absent that.