Where are you reading that? Alex clearly stated that the unique weapons are only reserved for the Executor. And when I suggested that the other ships could use a Kinetic blaster here and there to make it more unique he said he'll think about it.
Straight from the blog post:
Both the normal military and the Lion’s Guard get access to the Executor; the Lion’s Guard however are the only ones lucky enough to also have full access to the fruits of the weapons program. Their elite Executor variant is loaded for bear – with a pair of Gigacannons, and a quartet of Kinetic Blasters.
This at least gives me the idea that weapons program would be available to the Lion's Guard as a whole, just with an emphasis on the Executor as it's main "beneficiary".
You are still prioritizing lore over the gameplay and so far you failed to explain why elite forces are worse than regular ones. The dictators delusion is just a weak explanation, just relentlessly pushing for it wont make people believe it.
The problem is, there's nothing strictly wrong with it. Gameplay-wise, Lion's Guard ships act and function like slightly weaker vessels,
as intended. No one complains that the Colossus Mk.III's fighter bays are hideously kneecapped. You're treating LG ships this they're a 14th Battlegroup equivalent, which it's clearly not intended to be. You don't need to have a reason to use every ship in the game.
You're expecting an "elite" force to have the best equipment and receive special attention. The Lion's Guard receive both, in the form of the Diktat weapons program, Lion's Guard specific modifications, and slightly improved ship quality over regular Diktat patrols (fewer d-mods on average, as per
Alex's tweet). These are the "best" because they both came at the request of Supreme Executor Andrada. However, it subverts your expectations and does some storytelling, since the Lion's Guard ships in fact are worse off than usual due to the machinations of a deeply flawed governing body.