Here's my issue with Aaron being the Ripper. The Devil is in the details. If you are to take the eye witnesses, at least some of them, as having caught a glimpse of the Ripper here's the thing...The Ripper was viewed as neat and well put together, where Kosminski was described as unkept and dirty, wouldn't be washed, and so on....The Ripper was thought to have a somewhat rich anatomical knowledge and Kosminski, while I've read in some places that he had some anatomical knowledge, none of them seem to fit the description of how versed the Ripper would've been. These were just a few things dancing around my head before bed here I want to believe Kosminski could be the Ripper because it'd be nice and neat with the shawl stuff. But there are all these little things that bug me...
I personally like Chapman for the Ripper but that's just me