Turning off the feature doesn't sound so bad considering the CRJ-200 first flew in 1991, it took 26 years to identify the bug so I assume it's not used frequently at all.
I don't know about that, but it'd be a surprise to see an airframe of that age in commercial service that hadn't had its avionics upgraded, since that's a relatively simple way to gain new flight management capabilities. It'd also be a surprise to see so severe a bug go undetected for so long, if it was part of the original equipment.
