But that was exactly why it was still the best airframe for the job, as the early design was so overengineered for a civilian airliner, that it was so good for the job, especially at low level in dirty air over the oggin.........which is not something any of the newer anti-sub airframe design like the P-8 can cope with.
And the Nimrod had a large bomb/weapons bay running nearly the full length of the aircraft, as well as being capable of carrying external stores, it had a payload of around 10 tons, unsurpassed by any other Western maritime patrol aircraft before or since.