Its all in the wings
This is strictly a comment by someone else in an article that I recently read but I found it interesting from a historical aircraft design point of view....
"The B717-200 is actually a very good Aircraft, much better reliability than the MD80 and MD90's. It has a big disadvantage in its old wing design from the DC-9-33 made in Korea. Douglas stopped making competetive wings after the DC-8-62/-63, not having their own big wind tunnel like Boeing was a big part of it. A consulting von Karmann could only do so much vs. Boeings George Schairer working the Boeing wind tunnel. Airbus benefitted from the RAE and other European wind tunnels to design the Airbus wings. Hence without great wings an Aircraft design is crippled no matter how good the rest is."