Does format and quality (hires vs standard 16bit vs mp3) also make a difference in the impact/requirement of eq or no-eq?
If you were to put EQ aside, and let's just say, we use a track from... hmm. ok maybe i shall put it in my case.
I have both 24bit/96kHz and 16/44.1 for Daft Punk RAM album (Eagles as well). both high res and standard 16bit do have a significant difference, in terms of 3D "airiness" and "staging", the layering of musicality in the entire frequency spectrum, and vocals/instruments are tend to be more life-like (life-like in the sense that eg when the bass pad kicks, there are times when the kick isnt that strong or too strong, due to the amt of strength used to kick the bass pads)
I don't wanna talk about MP3. but if you're thinking of MP3 320 and 16/44.1 do not make any (or much) of a difference, you are right as well. But one must consider the type of recording and mastering behind that music. tbh, mainstream pop music, be it flac or mp3 320, it hardly make any difference. If there is a difference, it is insignificant to me at least.
now, back to EQ topic. the purpose of EQ-ing is to perhaps, either to bring out some emphasis onto a certain range of frequency, or to reduce it. So applying EQ to any quality of music, it really depends on where you wanna bring out in the frequency spectrum of that music.
Sometimes enabling EQ makes one's music to be less, or more enjoyable. but EQ is genre specific. so you cant basically have the same EQ for all genres.
I hope it answers your question, @sidrpm