H Div messes aren't run as boys clubs for officers. They have some of the least rule-driven messes in the army. They are formal when it comes to parade ground work and daily business, but the messes aren't especially.Fair enough.
Interestingly our Household Division has a reputation for formality. It has some of the worst manned units in the British Army - and is struggling to retain the few men it has.
Similarly our Lt Cav units are shitting kittens about producing circa two sub-units a year to go to Estonia.
Maybe focusing less on running these units as boys clubs for the Officers and more on units that people want to soldier in would be an idea.
Lt Cav have very formal messes but the units themselves are extremely relaxed, as all cavalry regiments are. I've never encountered another unit that was as free with the use of the word 'boss' or officers using blokes nicknames as the cavalry. Interestingly the part of these units that is formal, ie the mess, is near fully manned across the cavalry. Cav officers tend to sign off after their time at RD.
Many units have recruiting issues, but I don't think blaming formality as a blanket problem is especially accurate.