Betty -
Thanks for the frank assessment. It's interesting that while the trend in all things electronic and ISR is towards smaller and smarter, P-8A is and Nimrod MRA4 was bigger/more powerful than their predecessors. Some of that is accounted for by the fact that the targets are getting smaller and quieter, by MAC and its prodigious appetite for sonobouys.
On the other hand, range, endurance and weapon load are not vastly increased (unless low-alt operations are curtailed), and as previously noted the P-8A carries a big weight penalty because of AAS and ASuW.
Of course, another aspect of the problem is that there really are not many platforms to be had that fall between Q400/Saab 2000/C295 size and the A320/737 family.
What is really sad is that Airbus appears to have (a) a credible ASW suite and (b) an A319neo platform that should be able to outperform the P-8A, but that nobody likes the cost and risk involved in putting them together.