I play 3vs3 and 4vs4 because compared to 1vs1 and 2vs2, it matters more the strategy than the tactics.Sure in smaller mode you can flank more, but you can also lose if you just don't pay attention to a vet 3 grens,rifleman squad.I like tactics but if i really want only tactics i would play Battlefield.I play bigger game for the strategy cause you need to know what to expect,build and so one,if you don't build what you need at that right moment,then you lose.Also even if the games are more trench warfare, it let you think where you can flank,if is ok to lose 2 panthers to 2-3 jackons or firefly +some anti tanks.It's all about logic and a great plan,rather than just move some units and expect that guy to don't pay attention
Well, if you like to play those game modes, then I wont stop you. But the reasons you mention for them requiring more tactics seem to be pretty bullocks if you ask me. As if you wouldnt need to know when and what to build and expect at a certain time in a 1v1 or 2v2 (probably even more so, since you cannot rely on your mates to bail you out of the misery).
And I dont agree with your statement about flanks, usually its not about clever flanks but about your pack of tanks attacking another pack of tanks, nothing about flanks. There are simply too many units on the field to succesfully penetrate the enemy defense and to surpise them from the flank.
And lastly, the point about losing units: that's exactly what CoH is about, unit presevation distinguishes this game from many other strategy games. You even get rewarded for keeping your units alive. Losing two Panthers should always be a big deal, but not in those game modes, hence the "noob" image. You dont get punished for your mistakes.