Excuse my ignorance, if it can drop torps and sonobuoys and find and track subs than why would it be a bad buy? The planes size dosen't always denote capability.
"
CP-140M Aurora:
Long-range maritime reconnaissance,
anti-submarine warfare (ASW) aircraft for the
Canadian Forces. Based on the P-3C Orion airframe, but mounts the more advanced electronics suite of the
Lockheed S-3 Viking; 18 built" Quote from Wiki.
The S-3 Viking is a much smaller plane than the P-3 but had a better electronics suite. Maybe the P-6 will outdo a P-8. After all the P-8 is 14 years old, an eternity in the electronics realm.