Ships should be armed according to their designated roles, feature creep is a very real concern and what combat value you can fundamentally get out of a ship not designed for it is limited. What exactly is a "proper defensive suite and armaments"? I could see AOPS getting upgraded with a new cannon like the 30mm dual purpose system for CSC, remote weapon station machine guns and perhaps some limited EW suites against unmanned systems however, I don't particularly see the need for anymore than that. Once you start getting involved with decoys, ECM, missiles, torpedoes, larger guns, etc, you start requiring additional crew, additional space, additional funds, additional weight, etc. Return on investment capability wise is not there in my opinion.
At the end of the day, trying to turn AOPS into something it is explicitly not designed to do is a waste of time and resources.
Looking at everything from the perspective of a shooting conflict surely skews the value of a ship that is not designed to operate as a combatant. Navy's require a variety of platforms, not all of them are well suited to wartime operations or peacetime operations.
AOPS are great in that they provide a platform that is cheaper to run than a CPF but far more seaworthy and capable of a variety of missions versus an MCDV. They have great boat handling facilities, ample space for embarked forces, cargo space aboard, the ability to onload/offload cargo themselves, a great operational range and aviation facilities for future developments. Besides their designed role as a Northern capable OPV, there is great value in these ships for operations like drug interdiction, providing support to government agencies like the RCMP/DFO/CCG for their duties domestically, humanitarian assistance, security in regions like Africa, etc.
Just like how a CPF is a poor ship for many peacetime duties, AOPS is a poor ship for many wartime duties. That does not mean there is not a place within the RCN for either platform.