You're correct with that.
As a personal note, from what i saw in the few drafts i had yet, a good, average, bad ovr depends also on the position group. As far as i can recall, O/- D-Lineman and FS looked to have typically higher OVR ratings coming out of the draft. WR, TE, LB and QB especially seem to have lower OVR's coming out of the draft.
As a result of the above mentioned, yes. You will gain a sense of which pick was good with the time you've drafted.
Referencing from my drafts, for the QB section low 70 OVRs seem to be the really high rated guys. They also seem to be really rare, not like in madden 19, where there were 2-3 stud qbs every year. Which is great, because it creates a need for multiple franchises and you dont see projected first round qbs with good skill grades falling to the 3rd - 4th round anymore.
Obviously my sample size is to low to make a definite statement on that, it is of course only my subjective opinion.
nate__dogg is already working on the experience sliders, where he is evaluating 10 years of simulations. According to the previous evaluations, the default slider seems to generate enough starter qbs from the draft classes. If you want to know more about it, i recommend you to check out his thread in the madden sliders sections. Its obviously WiP but you can already get a grasp on the subject.