First I would like to say, that this idea is not to introduce two more full powered Heroes. I would like to see these two units to be consider as "Support".
Mablung and Damrod, available from the rangers camp (These two rangers feature in about three chapters of The Two Towers).
Mablung could weild a spear and Damrod a bow (as references in the two towers). They both have toggle weapon to a sword (It is mentioned in the book that they both weild swords as secondary weapons).
Roughly 2000 health. 20 command points, and cost 750 each. This is to ensure they are not as powerful as Boromir or Faramir, but they can be useful if used correctly.
I understand Gondor already have a ranged hero, but make Damrod have 30% less range, (reference to him thinking he saw gollum but was unsure).
As for skills I think the following would be appropriate and all the following abilities should be shared.
Warm Welcome (passive), Gives team mates (other factions on same team, not own troops), 15% Armour & 15% Damage (reference to how they treated Frodo and Sam). The main idea behind this would be whilst playing with a teammate, Mablung/Damrod could be used to support their faction, this would add another tactic that players could use, but it wouldn't be essential.
Long standing friendship, whilst both are on the field they gain 20% Armour. I felt that because they are always mentioned together in the books it would be likely that they would be friends and keep an eye out for each other on the battlefield.
Level 3 Strong Voices, Stuns enemies with fear (reference to when frodo and sam heard them). I have been thinking about this one, because Gondor already have a stun in the form of Boromir's Horn, it may be worth changing it to lowers enemies armour, otherwise Gondor could double stun.
Level 6, Guard Order, Roots an enemy in place, (reference to them looking after frodo and sam under orders). I don't think Gondor currently have a root skill, (Not sure).
Level 8, Stay at Camp, Whilst in the 50m of a rangers camp, production of the camp is increased by 15%, and the camp also has the features of a well. (This is referenced to how faramir left them back during the Ambush). This would change Gondors play style alittle to having a place to fall back on, similar to Rohans Bell tower.