I'm sorry if some of this is already in or just out of the question, just trying to make the Neutral factions the best they can be for I feel there is still much that can be done here.  If I recall correctly E:FE was about making the 'outside world' more interesting, this has been done but..

I think Neutrals should be able to expand to new camps if their population growth hits a certain limit (some should populate quicker than others - Oger/Goblin), the number & quality of troops they produce is based on the lvl of the camps:

lvl0 camp: Medium lair defense, No scouting groups

lvl1 camp: medium lair defense, replaced by light scouting group or two

lvl2 camp: Strong lair defense, replaced by medium scouting group or two

lvl3 camp: Strong Lair defense, replaced by medium scouting groups double in number

lvl4 camp: Strong Lair defense & gains a 'leader' unit of said race, Strong scouting group or two added, able to support 1-2 new camps (depending on race), gains    diplomacy

lvl5 camp: Deadly Lair Defense, Deadly Scouting group added, able to support 1-3 new camps of said race

When the new neutral camps are formed they are 'linked' to the same faction that produced it.

When the new neutral camps are able to produce a leader of their own (new camp turns to lvl 4) then there is a certain % that the new leader will either claim the said camp as his own or will side with the previous leader - chances depending on race/intelligence

Diplomacy

I don't want to have to manually control the minor factions/neutrals, I want to watch(help) them grow & become something they might not normally become, a massive Empire by allying with them & sending them whatever kinds of resources they use (Perhaps the 'food' resource would be the way to handle this, one could designate how much food to send to the minor faction causing it to grow accourdingly).

I believe neutrals should have standings with other neutrals, like a war between the Ogres & the Wildlings should be feasible

& Please make it so that we can see what our allies see (this should help the ai as well?)

Territorial borders

I think most all neutrals would have a certain area of land they call home, the territorial borders I'm suggesting for the minor factions is more of just a 'warning' line to show you where the locals know not to go.  This could overlap/ignore Major faction's influence borders, and give them a way to have relations with other neutrals/factions close by.