Even though it is a bit offtopic:
and 1 Gondor soldier can easily defeat 10 orcs, because they are such highly trained warriors.
Waaaait... what?^^
Yes, they were highly trained, but one Gondor soldier would never won against 10 orcs. Perhaps if they only attacked one by one, but Tolkien always tried to be realistic and even though the orcs had not such a special training, they weren't bad fighters. And even 3 medium fighters would probably be able to kill one good fighter, if they attacked at once. So why should 3 orcs, who also learned fighting their whole live, not be able to kill a gondorian soldier?
Tolkien always tried to be realistisc and never created such "unkillable mass slayers" as characters in the third age. In the first age such heroes were possible, but not while the war of the ring.
Even the fellowship of the ring with 3 skilled fighters (Gimli, Aragorn, Boromir), one wizard and one archer (and 4 hobbits) had problems with killing <20 goblins.
And Boromir was described as one of the best fighters of Gondor.
So why should 2 normal soldiers be able to stand a better fight than the whole fellowship of the ring?
Additionally you hate to take in account that, especially in Osgiliath, the gondorian troups were surprised and not ready for an attack and additionally the nazgul destroyed there whole moral. Another point why the orcs are really strong.
For me one of the well trained gondorian soldier would perhaps be able to kill 2 orcs at once, but not more - with the demoralized mindset because of the nazgul perhaps 1, but not more.
Even while the battle of Minas Tirith Mordor only had four times as many troups as Gondor and Rohan together. And they sieged the whole castle, therefore lost many troups without being able to answer their deaths.
In the battle of Helm's deep Isengard also only had about 2-3 times as many troups as Rohan if you use the numbers of the 4. march (which was when Erkenbrand arrived with 1000 troups)
So it would neither be book, nor movie-friendly when we'ld make the difference between orcs and gondor soldiers bigger.
The Rohirrim could not have saved Minas Tirith alone without the help of Aragorn and AotD.
Depends if you use the book or the movie - in the books the AotD never reached Minas Tirith. The Mordor army was surprised by those two armies as they didn't expect them at all, but expected reinforcements. Therefore they also panicked and got killed easily.