Regarding the Martin B-26, it acquired the 'widowmaker' reputation because it had a high wingloading (for its time) and was too much for green pilots during landing or single-engine work. In the hands of experienced pilots, it performed very well and had one of the lowest loss rates in the USAAF.
Adding wing area decreased the wing loading (thus negating the "Baltimore whore" moniker - short wings = no visible means of support) and it became a non-event as the war progressed.
Also consider the Avro Manchester - underpowered and with overworked engines tending to overheat and catch fire, it was developed into the outstanding Lancaster.
See also the Short Sterling - incredibly high loss rate due to the pre-war hangar door restriction on its wingspan. It flew lower than the Lancs and Halifaxes and subsequently was shot down at much higher rates. Eventually, it was withdrawn from bomber ops.
The outstanding North American F-86 Sabre was called the lieutenant killer in the early days of jets. Subsequently became one of the best first generation jet fighters of all time. I think you'll find rushed or poor training as the cause of most 'widowmaker' reputations vs design flaws.
Good luck in your production, just be accurate.