I'm going to throw this out there to see others opinions.
Something mentioned in another thread once again brought to my mind the question of sight radius.
For 46 years I've seriously played with firearms and for some periods of that time fired a gun of some sort almost daily. I've yet to be able to look at my shooting or someone else's and say the results were due to sight radius.
Good shooters shot good, suckie shooters shot sucky, regardless of sight radius.
I once had a S&W 19 with a 2 1/2 barrel and with wadcutters it could stack them on top of each other at 25yds, just like a 4". Glock 19 or G17 which one shoots best in my experience depends on how it likes the load and might as well throw the G26 and G27 in there too. Iron sighted rifles? 18". 20", 24" bbls it depends on the day and ammo seemingly.
My way of thinking it is all like a Venn diagram with a whole lot of overlapping based on trigger, sight, weight, ammo, etc weighing in on how much overlaps.