I tend to be heavily driven by data and analytics. Even back when I was an athlete. My teammates would make fun of me and call me a robot. And the spreadsheets I'd make, for example ones based on the results of each play type we'd run, didn't help.
I played basketball and was our team's shooter. I would get yelled at by my HS coach (and even benched once) for taking "bad three's" as opposed to stepping up into a more open 2.
I had to literally give a presentation explaining that he was asking me to hit 50% of those 2 pointers in order to get equal value from me hitting 33% of those slightly harder shots. Afterwards he let me play my way. This was back in 2002, and I didn't know at the time I was basically explaining what is now know as an advanced stat called Effective FG% to him. Almost 20 years later ~40% of shots in the NBA are from 3 bc of this logic.
I've always loved stats, math, and analytics and believe they absolutely should be incorporated into sports. But the main key to doing this is to understand the variables you aren't accounting for and acknowledge the ones you can't.
All of the factors you mentioned are valid. Also, maybe smaller players tend to be in better shape. We can always try to dig deeper. The study I posted is limited and should only be taken for exactly what it is. I believe analytics get a bad rap bc many that use them don't appreciate the nuances or understand the limitations. Like if somone read what I linked to and thought it's implying it's a good idea to build a team of undersized players, they're doing it wrong.
I'm very interested in analytics too. My biggest issues are:
A. People tend to like what they like and ignore the data, OR
B. People get so focused on the analytics that they misunderstand how the analytics fit into the big picture.
So, for me when analyzing an NFL prospect the biggest element is the film. I use statistics like combine numbers to verify what I saw on film. So I was a huge Mike Gesicki fan because on tape I saw a rare athlete in a huge frame who made tremendous strides. He went from a skinny volleyball player who just barely learned how to play WR to being converted to a bulkier TE in college. He went from being a kid who had bad hands to becoming THE BEST contested catcher in his draft class and vice-grip hands. When the Combine came around and revealed he was 6'6, 245 lbs., with long arms and a 41.5" vertical ... it was not a surprise. It merely confirmed my view of his physique and athleticism. The film already explained how he was exceptional at high-pointing the ball. The Combine measured bench press, but not grip and rip strength to snatch and hold the ball, so that element wasn't quantified, but was obvious on tape. While his route running was so so, it had improved significantly and he showed to be continuing to improve. His blocking was poor and his blocking effort was poor, but his coaches simply didn't stress it with him, so that was an open evaluation.
When the higher level analytics compared him at his position vs. other prospects and he showed up in the very top tier of length etc., it was no surprise. But, despite his fast forty time of 4.56, it was clear that he was a long strider, and despite his 41.5" vertical, he wasn't bursty out of his cuts. The stats didn't really tell that story, but the film did. Ideal weapon for seam routes, red zone throws, 3rd down throws, and check downs. That profiles fantastically to a Move TE. I was a huge fan, advocated for drafting Minkah Fitzpatrick and Mike Gesicki, and when we drafted them 1, 2, I was ecstatic. Unfortunately, despite me advocating to use Minkah in the FS role exclusively even before we drafted him ... we foolishly didn't, he was disgrunteld, traded, and became an instant-All-Pro at Pittsburgh as they played him exclusively as a FS. I explained how Mike Gesicki would need time to transition as all TE's do ... and he has. I'm ecstatic to see him growing into the potential his analytics showed.
But, IMHO, most people try to treat football like baseball ...but we don't really keep track of the right statistics to quantify it the way it is so well quantified in baseball. Our RB's are so dependent upon their OL, the defense presented, and of course down and distance. Averaging 5 yards per carry looks great unless he's only used on 3rd and long. The RB able to average 3 yards per carry who is only used on 3rd and 1 is the better football player, but we cannot capture all that data into one stat, so it tends to be misleading in football. In baseball the On Base Percentage is a great metric, like the Slugging Percentage or Earned Runs Average. We simply do not have those equivalent metrics in the NFL. So when people compare QB's ... there's just less definitive data, and we need to over-rely on things like YPA. When we look at pass rushers, we over-rely on Sacks and it's even hard to compare Pressures because some teams use stunts and blitzes more than others or play coverage and leave their pass rushers to win 1v2 a lot. Whereas in baseball, essentially, every batter is isolated depending very little on any teammates, and every defense is essentially the same. There are a lot less dynamic variables to throw off the game statistics.
In football, we tend to rely more on athletic statistics of the player (40 time, vertical leap, height, wingspan, weight) than their actual play, so there is much more of a disconnect when evaluating players. I'm sure you are just as excited as I am about where analytics is headed and can't wait for the analytics world to start reaching deeper into providing meaningful data.
Of course, we're always at the mercy of the human element, because no matter how much data analytics provides, it's still the individual who needs to weight what is important and prioritize what they want. :)