I don't see the LF battery being tested on heavy cruisers - and the 10 Monsoons that were retrofitted, don't forget them - before finally being fielded on the McKenna once the concept was proven. I instead see it as purely economics and political demands.
Not every decision is made due to doctrinal or technological reasons.
I don't disagree. "Tested" is perhaps too strong a word. Cruisers certainly would have made sense as the first place to use LF batteries. The batteries certainly seemed to give heavy cruisers a new lease of life, if only for 100 years.
Service would have shown cruisers would have been insufficient on their own, and the finance guys would have seen firepower per LF battery as a similar bottleneck to collars per jump core. Given the expense it only makes sence to pack as much combat capability into a single LF battery as possible.
They also wanted for things that a McKenna would've been overkill for. IIRC, the Luxors' first assignments tended to be guarding convoys going to and from the Periphery. Not something you waste a McKenna on, but OTOH more than what a ship of the Luxor's capabilities should be assigned to. But remember, this is the same organization whose idea of crowd control was the Magi.
cheers,
Gabe
Mainly because that was the main job for the fleet at the time (2765).
An SLDF escorting formation would have been made up of several parts. Sov Soys and the DDs would have been the close escort, protecting single convoys.
The LF ships would have been distant escorts, responsible for shepherding several convoys. These guys are being called in if the close escort can't handle it. Arguably a perfect role for a battleship.
Remember in 2765 the Periphery had effectively no WarShips. Yeah the RWA is running Hegemony assets, but they are also being taken to pieces by the fleet. The rest of the Periphery is running an asymetric war. ASF, nukes, crazy janes, merchant raiders. The stop and search stuff a Sov Soy and its DropShips are made for. The distant escort is only jumping in if Tirpitz comes out to play, at which point the gloves not only come off but knuckledusters are applied.