I'm not seeing the part that's negative here. The more aid we can render the better things will be for the North and potentially beyond.
To be fair, we can put multiple retainer actions on Render Aid, or Dreng, or whatever.
I just don't want to expand because the narrative behind it is displeasing for me.
There is also the politics angle.
The larger our personal guard, the more importance we imply on our person. if our guard is greater than that of the King's for example, are we not saying we are more important than the King?
Because that is what the Hearth Guard is, our personal guard retinue.
This is also why these formations tend to be on the smaller side: The primary purpose of such guard units is traditionally to guard their Elder, to whom said guards have tied not just their fortune but also their honour upon until the end of their life.
We're just being extra odd for an elder, and commanding our personal guard to leave our home; not protect us (which would be the expected task), but rather go forth help other dwarves.
We're powerful, and well regarded enough that this is called eccentric rather than barking raving mad (because it goes completely contrary against most established traditions regarding personal guard units).
This doesn't matter for a small unit, because it is expected for an elder runelord of our stature to have personal guards, and what a few personal guards do is no one elses business to anyone expect said runelord. Their honour is the same as our honour.
We can get away with our current unit or maybe slightly larger, because we keep them busy; We have a clear and constant need for our current retinue, even if said need is odd from the point of view of your average dwarf. 'That's just the Gift Giver', they say. We're known by reputation as an odd duckling anyway.
Basically, having a rotation of guards around? Expected. Having several extra shifts of guards around in addition to the basic rotation? Well, instead of just standing around, wouldn't they be better used doing something? Particularly given that they experienced elders in their own right - they could be contributing with training the younger generations or whatever their expertise would allow them to do. Opportunity cost, in essence.
But as long as there is a clear need to match the numbers, it's fine.
And yet this excuse gets thinner and thinner the more elders and experienced dawi we begin to command. if we wanted a cadre of rangers to scour mountaintops for lost Dawi, why have we made these rangers our personal guard rather than discuss with the head of rangers in our hold? After all, we clearly believe there is an issue of lost dawi, a serious one at hand given how we keep sending our personal guard in great numbers to tackle this:Are we implying the standard ranger forces can't do their job? Are we usurping the mantle of responsibility from those rangers? Are the ranges of our hold incompetent, is their leading elder inept?
Same for healers, miners, etc etc.
As our numbers grow, we need increasing justification for those numbers to make sense in a wider Dawi society and to account for the opportunity cost implied. At some point being odd and eccentric turn to being regarded as being excessively prideful, then selfish etc etc.
So we don't want to bloat the numbers of the Hearth Guard just because we can. We should increase them only if we see a clear reason to do so.