BI,
Planning on doing any deep field ASW (or even ASuW)? Say to counter a potential SSN-19 threat. How far out is your Merlin going to operate? How much time will it spend transiting to and from the CV, and how much time will it have on task when it gets there? Get a hint of a contact 100nm from your nearest asset and time late becomes a factor in the area size to search when you get something there, compare transit times for a 100kt ish asset vs a 300kt ish asset.
ASW and ASuW done properly are multi platform events. An MPA isn't the sole answer, neither is a helo. Each asset has its own strengths and weaknesses, and plays a part in providing a layered solution. One of the layers has been removed, end of story......