I don't quite get the anti-P-8A vibe going on here; it is a new platform which is clearly developing and has HUGE potential. Yes, it is not fulfilling the full role that the older brother is able to do but the MRA4 would not have completed the tasks of the MR2 to the same level for quite some time. The roadmap is there to get to that level, and beyond......the Aussies will have timed their purchase well.
We have no MPA and have no aircraft that we can class as multi-mission in ISR terms(standing by for Reaper mates to shoot me down).....we need one. We are still investing in legacy platforms that deliver in only one area ie E-3D and Sentinel; both are fantastic at what they do, but why not have that capability on board a new frame that is more fuel efficient, easier to maintain, longer lifespan, more potential etc etc. The P-8A has all of this. Should it be fitted with AAS therefore becoming the AGS, it will have the overland radar piece squared away nicely.
In terms of other contenders, the Saab Swordfish and the CN-295 could be decent alternatives for a lower financial outlay but wouldn't cover the full capability of a Poseidon. Or do we go down the route of re-engineering old airframes a la P-3C/CP-140? Risk v proven capability v finance?
Biggest issue for me will be manning this MMA with the correct personnel and with the required experience and ability.....that is shrinking fast.
Convinced it will happen to the same degree as I was convinced MRA4 would never enter service.