- Dwarves are notoriously heavily armoured and dangerous in melee, meaning both arrows and infantry are ineffective against them. They're slow, but seeing as how Third Age places a greater emphasis on city sieges...
- The High Elves can recruit an "archer" unit that not only has the longest range in the game and fires arrows which can kill most heavy infantry units through their shields, but also has armor and a melee attack greater than most infantry and can match the speed of the fastest cavalry. You might be tempted to scream at the cocky Noldor elves when cheap enemy infantry surge in on your very expensive and difficult to recruit archers. That impulse will likely go away after the first time they butcher and rout the orcs that hit their lines and then merrily execute the fleeing survivors with arrows to the back. The only thing slowing the High Elves down is that they start off in the campaign in a fairly poor position with limited expansion options. (Dwarves to the north, Eriador to the east, Rohan to the south). As a result, expansion as the High Elves is slow and you won't be able to build a big, potent economy for a long time, so your armies will be rather small, unless you're willing to go totally against the lore and start conquering the other "good" races.
- The Silvan Elves as a whole. Even their basic Light Elven Archers have range and firepower comparable to most other factions' best archers, and the Sentinels that are their second-level archers are excessively long-ranged, hit hard and have excellent melee capabilities as well. Because of the versatility of their archers, it is possible to have the lion's share of any Silvan army be made up of Light and Sentinel archers, which will utterly butcher any army trying to charge them. Sure, their melee infantry aren't that great, but when 75% of the enemy army is already dead by the time the lines meet, and the archers are just as good in melee as the dedicated melee troops, they don't need to be. It's possible to destroy an entire enemy army that outnumbers yours two or even three to one, with trolls and wargs, while only taking a couple hundred casualties at most. Hell, the Silvans' ranged capability is so great that they can siege and assault small fortresses and villages without setting foot inside them. Casualty-free victories are not only quite possible, they're almost expected when playing the Silvans.
- The only thing that beats the above archers are trolls, which will beat them with absolutely no effort or direction from the player. If you see trolls on the other side, regardless of what your faction or army composition is, resign yourself to losing 300 men off the top. Oh, and trolls are also as fast as cavalry and can even climb siege ladders because they are coded as infantry.
- The Free Peoples of Eriador are actually one of the weaker factions, despite the large territory they control, mostly having militia and irregular troops... unless you bide your time, build up your economy, and eventually build the Hall of Kings to reestablish the old Kingdom of Arnor and get among the very best troops in the game.
- The Balrogs that spawn in Moria are, as you'd expect, quite capable of butchering entire armies of elite soldiers.
- Rohan has an excellent starting position, multiple avenues for quick expansion and one of the best all-round unit rosters in the game. Their strong economy makes it possible for them to rapidly build up a powerful core of well-protected settlements that can churn out armies of heavy cavalry and armored swordsmen that can easily crush Isengard while it is still in its infancy. Unlike many factions, the majority of Rohan's best units are available before the 10-year Wartime Production event occurs, allowing them to gobble up vast amounts of territory with comparative ease.
YMMV / Third Age: Total War