To be fair, it's not like this isn't standard industry practice. Airframe evolve and change, with incremental changes typically only affecting limited areas of

To be fair, it's not like this isn't standard industry practice. Airframe evolve and change, with incremental changes typically only affecting limited areas of impact. OTOH seeking a non aerodynamic solution to a significant stability degrading airframe modification was IMHO a bridge too far. If the pitch stability (not the pitch feel) problems couldn't be dealt with aerodymancally without busting type certification, than perhaps the whole concept was just too much of a stretch for the venerable old 737. It surprises me, though, that this couldn't have been engineered out with enhancements to the horizontal stabilizer, such as tip fences or a span increase to offset the lift from the engine nacelles. If it could have, but software was cheaper, then that's even a darker indictment of Boeing's engineering incompetence.