There are upsides and downsides to 1v1'ing.
It can void the map of solos and small groups, because there is definite action at the 1v1s. They would rather go where they know action will be, than spend hours only finding a couple fights here and there that might get away. Yet, I do not consider this farming. You consent to the fight, and usually have a fair chance of winning or at least believe you do. If the other side depraves themselves of "I win" buttons then you certainly do have a chance given an equal skill level and class matchup. Wargs can beat a spear warden at 1v1 and leave both needing a rez. This is exactly what differentiates it from farming. Farming is facing the same unskilled, unresponsive player over and over and over again knowing the outcome is predetermined. Farmed players do not fight back, or have the intention of beating the one farming.
1v1's are not always the best way to learn how to counter the opposing class. Rarely does the other player deprive himself of "I win" buttons in an open map fight, and when this happens you will not know what to do, since you didn't encounter this in the 1v1. I've seen a Rank 11 LM stack 3 Waterlores on himself before blasting my, at the time, r2 warg into oblivion. I've seen wardens pop DC the second my warg pounced while the second warg waited to pounce after stun immunity. A weaver popped reflect the second a 1v1 started against my warden... these are all situations that are not typical in a 1v1. Large groups vs solos, or clear keep "farming" is much more akin to farming than a 1v1 circle. Yet I would not rely on the 1v1 circle to learn all your skills, movements because you aren't facing the same situation if you were solo.
~Anaxander R9 Warden, Baranthor R5 Hunter, Skartan R2 Guardian~ Elendilmir
~Karukh R10 Warg, Prisonshank R6 Reaver~ Elendilmir