Goblins:
Gundabad
Misty Mountains
Moria
reguarding the goblin minifactions
I would replace misty mountains by goblin town
I thought there was a Northern Kingdom though.
as far as i know the most northern kingdom still in place by the end of third age is Dale
witch could be a really cool mini faction for dwarves
i dont think that transforming buldings is a good idea id rather make like per example 3 different builder you can recruit at the fortress
depending on the minifaction and then they build the buildings of their factions
wut would be even cooler is to have like one fortress with three big build spots that generates a partial minifaction fortress and then theese partial fortresses have build spots for conventionnal defences
k let me give an exemple lets take the men of the south
the main fotress is a big tent
than theres three circles
you select on one circle
now u have the choice to add on:
1- a haradrim tent that helps you summon harad heroes, gives a certain bonus (eg.: harad buildings near fortress builds faster and cost less), range of upgrades ( eg.:spikes or fog ) and 3 spots for defensives structures (eg.: a hunting post that feeds (heals) nearby troops or a simple tower)
2- an umbar trade market where u can summon umbar heroes, gives a certain bonus (eg.: boost on ressources from the forteress), range of upgrades ( eg.: lamps that widen the vision of the buildings) and 3 build spots for economic structures like markets that acumulates ressources or shipwrights that lowers the building time of boats.
3- i think you get it...