You know guys, leveling, staying after death, knockdown and all... a large addition, right?
For a start I would suggest making dogs NOT WORHTLESS. For example making them at least a bit stronger than brahmins, which are free and easy to get. Dogs have less hp, less damage, less damage resistance and outdoorsman at a similar level... And no, I didn't use the always-outdated wiki. I checked it ingame. If I weren't that much about atmosphere and dogmeat nostalgy, I would use brahmins instead of dogs and have a bigger combat advantage than tagging along with those worthless mutts...
Dogs costs 500-1000 per one. Brahmins cost 2xfibre. I know that the former shouldn't be a master-killer, but giving them 40 or 50hp (instead of 34) and about 2-8 damage (instead of 1-6) would place dogs nicely between free brahmins and 1000-2000caps HtH mercs. This is just reasonable.
EDIT: just btw, but raising dog outdoorsman has drawbacks also. My friend has 100 outdoorsman (which is enough to cover most of the encounters and travel quite safely) and he don't like when I take my dogs when we hunt together, because it don't change encounter check too much and he doesn't get xp for them...