I thought this idea was quite genius
The Tribute camp now will not gain resources and you cannot build it in castle's, camps or outposts. Instead you can only build it in settlements.
When you build a Tribute camp you will have 3 options to choose from: tribute to Rhun or Harad or Umbar. Once you choose a faction you will have a choice of 3 units to call from but at the start you are restricted to one of the units because the other 2 units require certain things to unlock. Let's say for example you choose Harad, there are 3 different units you can call:
Unit 1 Haradrim archers
Unit 2 Haradrim cavalry
Unit 3 Mumakil
If you built one Tribute camp and choose Harad you can only call the Haradrim archers at the start. The Haradrim cavalry requires level 2 Tribute camp to call, in order to unlock the "Upgrade" option it requires Sauron's influence on the Tribute camp. Sauron's influence on the camp basically allows you to upgrade the Tribute camp building. Now to call the Mumakil you need two things, you have to upgrade the Tribute camp to level 3 and you need a new Passive power that replaces the "Haradrim reinforcements" that basically allows you to call the Mumakil or Unit 3.
Bear in mind that a single Tribute camp only calls one battalion of each unit. That means if you want more units you can build more Tribute camps and each of them STILL calls one of each unit with recharge times like the call reinforcements power. Also the more Tribute camps you have the less recharge time of spellbooks. The power "Rhun reinforcements" is now replaced with a passive power that allows you to PURCHASE upgrades for those units.
So now that I have explained, here's the units of all factions of the Tribute camp:
Harad:
Unit 1 Haradrim archers
Unit 2 Haradrim cavalry
Unit 3 Mumakil
Rhun:
Unit 1 Easterling pikemen
Unit 2 Soldiers of Rhun (these are the ones called Easterling halberdiers but I would really suggest to change them to pike instead of swordsmen like bfme 1)
Unit 3 Easterling hero unit with special easterling leadership
Umbar:
Unit 1 Corsair swordsmen
Unit 2 Corsair Knife throwers (ranged swordsmen unit similar to haradrim spear throwers strong against pikemen)
Unit 3 Corsair Fire bombs throwers (ranged unit very strong against buildings)
Each faction is powerful in unique way. Harad has powerful cavalry, Rhun has powerful pikemn and Umbar has powerful swordsmen.
I also think that slaughter houses can now be built in camps and castles instead of the Tribute camp.
And I believe you should consider implementing it some day (After all the factions are in, or if it's easy to do, a patch)
And I thought of what could replace the tribute camp in your base.
Tribute of the dark lord
This would have a statue of Sauron in it, along with a small house (with the normal Barad-dur look you've been going for)
.
And a small fence surrounding it.
And in that fence would be Black uruk archers(they'll fire if you have the defence upgrade at level 3).
1 2 3
The bonus would be a cost reduction to heroes (5% 10% 15%) maybe up to 20% if it's not too op.