Too early to make the call on the last two drafts and what has changed since the 3 year rule in judging draft picks? The only thing that's changed are our expectations; it still takes time for lineman to develop and we get one OL to make All Pro, for the first time in 60 years, and the exception become the rule. Larry Allen needed time and he got rag dolled by Reggie White as part of his indoctrination.
That 3 year rule came into play before FA and most didn't even see the field in real games in year 1 but I think we can apply less time now except for one position, OL, other than LT. The spread offense in college was created out of necessity because of the lack of enough quality OL to go around. The reason Yosemite and Martin came in so ready was because their HC's at WIS and ND played a pro style O featuring the run. Conner Williams had to convert from OT to OG coming from the Big 12 plus bulk up to fit the position, he's definitely a 3 year evaluation. Look at La'el Collins progress since he came in and he was a 1st rounder.
The other thing we do is take year 1 as real too often as we did with Prescott and Gallup and both struggled in their 2nd year, just as we're seeing Mayfield struggle.
Hill is different, he was available in the 2nd for different reasons and that is becoming a problem.
A lot of college players can get by on their brawn but once they get to this level, their brawn is seldom that much of a difference. Now, they have to learn to use their brain and for some players that takes longer. Players like Kuechly and Lee are the exceptions.