Bearing in mind at least one problem with the Comet, such as no L/E devices and hence the ability to stall the aircraft by over rotation, the rectification of which took plenty of time even after the events of 1954, I wonder whether the aerodynamic work on the DH121 was perhaps a bit under-resourced and rushed especially as the lead customer BEA couldn't seem to decide what they wanted until pretty late on in the process. Having a very experienced pilot like Cunningham has its good and bad sides, good because he was likely to do a good development job, but then possibly leaving average pilots at a disadvantage with any tricky handling characteristics.
Maybe the Trident was not quite late enough to make use of the lessons that were being learned by all manufacturers about designing efficient swept wing commercial aircraft during the first decade of the jet age.