This has been rolling around in my head some time. Generally it falls under the category of undead but (from what I know) the majority of undead spawned using the animate dead with no corpse are zombies, forcing a player to have to find raisable bones in order to make skeletons.
The Carrion Feaster summons ghouls, why not give the Bone Warden his skeletons?
Why add skeletons? Flavor. Some like the idea of an army of bone minions rushing the battlefield at their will as opposed to a slow, shambling army of rotting zombies. Instead of simply giving Bone Wardens raisable bones each reset, the 'Skeleton' theme could be applied to them in the same manner the Carrion Feaster gets a 'Ghoul' theme.
I realize this might be asking a bit too much, but I would greatly enjoy seeing something like this implemented. I'm sure it would see a lot of use.
EDIT: I don't want this used as a SUMMON CREATURE sort of summoning theme. I want this to be an ANIMATE DEAD sort of summoning theme, to clarify. This may restrict the use of the 'theme' to the Bone Warden perk being that it can't exactly be put on the theme NPC for only affecting Animate Dead, but I'm very open for suggestion on this, because I want this!
like the carrion feaster summons ghouls yes? This is rather viable, makes sense. This is nice, and i'd like to see it.
Replace bone wardens default animate dead with a pissy skeleton. Not completely unreasonable I suppose, seeing as it should be more frail than a zombie if maybe resistant to blades and such.
Brittle Skeleton. As weak and easy to shatter as a shambling corpse.
Or make it 25% slash/pierce resist and 25% bludgeon vulnerability. Plus lower hit dice than a zombie.