To clarify, it's not just the big-time speed guys. Taking the extra base. Getting good jumps/reads. All of that takes a hit for a decent percentage of our players. It's weird. And McLouth went from, if I remember correctly, one of the highest (success) percentages in history to just an above average baserunner.
Bourn dropped from 13.6 to 7.8, McLouth from 9.0 to 2.1, Upton went from 0.9 to 5.0 so far this year, Heyward is also already higher this year than last, Blanco went from a 0.5 to a 5.7, Giles from a 0.8 to a 4.7, Renteria dropped from a 5.3 to a 0.8, BJ from a 5.3 to a 0.7, Cabrera went from a 0.0 to a 3.6, etc - I think there is enough evidence to support that it is something wrong with our system/approach. The difference in roster is just selection trying to overcome a weakness by avoiding those kinds of players, instead of finding and fixing the problem.
This is a pretty selective use of the numbers. Let's run through these: Bourn dropped from 13.6 to 7.8 but clearly had a 3-year peak, and we got him as he was coming off that. He was 6.7 in 2008 before that run, and he's been at 3.9, 0.6, and 2.1 in the last 3 years since leaving Atlanta.
McLouth dropped from 9 to 2.1 but the 9 was by far his best year ever. The 2.1 came in half a season with Atlanta, he jumped to 3.4 in half a season with Atlanta the following year, was at 3.8 in 89 games the next year after Atlanta, and was under 6 in a full year the next.
Renteria had a run with these numbers prior to coming to Atlanta: -1.3, 3.8, -1.7, 1.6, -2.5, 5.9, 2.2, 5.3. He did drop to 0.8 his first year in Atlanta, then rebounded to 3.1 his second year. What did he do in the 2 years after Atlanta? -1.6, -2.8.
It seems to me the common thread here is that we got each of these guys around age 28/29, right after their peaks as base runners, and Atlanta coincided with a downward trajectory for them. There is no obvious trend of being great elsewhere and worse in Atlanta here.
Heyward? Yes, he is at 4.4 this year already after posting a 3.4 last year and a -0.6 in an injury-plagued year in 2013. But even this year doesn't come close to the 9.7 he posted in Atlanta in 2012. Why would he get better over the last couple years? Maybe because he's healthy and he's 25. We let him go just as he was getting near his peak, which seems to be about 25-27 or so for base runners.
You use Upton's comparison from 2014 to 2015 but don't use the fact that he was 3.7 in 2012 with Arizona and 4.1 in 2013 with Atlanta.
And Gregor Blanco? Seriously? He had 48 PAs in 2009 when he posted that 0.5. What did he do with a full year the year before? 3.7. He did post 5.7 in 2012, then fell to -0.5 and -0.2 in the years following.
Marcus Giles posted 0.8 in his last year in Atlanta. The 3 years prior? 5.6, 3.1, 3.5. In that sense, the 4.7 is mostly just more of the same; makes the 0.8 seem like a random outlier, not a product of bad base running coaching/techniques in Atlanta.
Melky Cabrera? Yeah, he sucked in Atlanta. Even still, in the 3 years prior to that 0.0 in Atlanta, he posted a combined total of 0.5. And he's been awful the last 2 years. Seems like perhaps that two year uptick coincided with a two-year uptick in offensive numbers as a whole. What could that have been?
And lastly, BJ. Again, BJ also sucked in Atlanta. And he sucks in San Diego. He did post a 2.5 last year in Atlanta, though, and posted a 0.9 in TB the year before that 5.3.
So, yes, you used extremely selective numbers to make it look as bad as possible for these guys' years in Atlanta. Taken as a whole, Atlanta does not in any way look like an aberration.