A few thoughts.
The forward gun seems to have restricted arcs on the merchant look-alike bieng closer to the superstructure and the mast and boom might interfere too.
There is less room for the electronic equipment/ aerials on the masts
The AA defence seems lighter too.
The higher freeboard would give better seakeeping and it might be cheaper to build.
One side effect is your enemies target every merchant you have incase they are disguised escorts. Still it is a fiendishly good plan