I favour matches from 2v2 to 4v4 in size, though I seldom play the various mods which constitute the majority of server activity.
Matches differ in the mix of skills they require to play effectively just as they differ in size. In one on one games, the social dynamic is limited to gauging and countering the actions of your opponent. Many of the players who are drawn to one on one prefer this limited social component, indeed you'll see that some attempt to minimize even this in favour of concentrating on input factors like manual dexterity or personal skills such as contingency planning. However, skilled one on one players often invest heavily in the social-intellectual competition and even forge friendships through it.
As games scale up, the effective social requirement grows with the number of opposing forces and the number of allies - gauging and countering effectively becomes more difficult because there are more variables, and cooperation as a collection of social skills enters the picture. Effective cooperation is not easy, it requires you gauge your allies actions and personal skills like you would do for an opponent, then ascertain what you or your ally must/should do, and then communicate this clearly in a way which can be quickly and accurately processed. Input factors and personal skills remain, for the most part, what they were in one on one - however, problems often arise when a player allows his or her focus to narrow to the section of the territory which their units populate, and trust their allies blindly. This is a mistake that players of various grades and preferences make often; we should all remember that no matter how many people are participating, you as an individual must pay attention to the entire field of play in order to do your part effectively.
I'm sure some people are beginning to seethe here, since by this metric the most skill intensive matches in an ideal situation are the largest matches which can be played, both in terms of players per team and in number of team participating. Let me clarify; we are nowhere near this ideal situation.
Remember that the selection of players in the community is limited. Skill variance may not be as wide as in more popular titles, but there are fewer people and thus the jump from player #313 to player #29 will be comparatively more severe. With fewer people and steeper jumps in ability (Input, Personal, Social) from individual to individual it becomes difficult to create a good, balanced match, and this difficulty increases with the number of participants you desire. One on one matches in Spring are, with few exceptions, categorically superior to eight on eight because the balance between the participants is much tighter and because there are fewer factors frustrating play. Fewer players, a purely competitive social dynamic... and nobody forgets that the whole map is their responsibility.
Why, then, do I prefer games from two on two to four on four in size? Well, I play 1944 for the most part. We have a tighter if smaller community, and while we have great variance in ability, we know where - generally speaking - most people are in relation to one another. We can manually balance and thus can create small team games which are usually good and balanced. I can bring my cooperative social skills to bear as a benefit, and we can have more people involved at once. I play one on one in 1944 if I think that the match will be good and balanced within reason - that is to say, if I can feasibly win at least one in three games and my opponent is in a similar position. I used to do similar in BA when there were more active players around my skill level, and if I had the time I would probably take a similar stance in CA.
