I personally find that playing solo develops your skill individually, and at a very fast rate, where as those who team are stuck in a never ending loop of depending on someone else to help them out whenever they are in need. Although putting that aside, teaming is also a great way to develop teamwork and to make many friends within the community. My take on the situation is that many people have tried solo, and then come to the realisation that they stand zero chance winning by themselves, which then starts the chain of their MCSG career (Bad player --> Teams for wins --> Never becomes better --> Continues to team for wins). In short, I am a big believer that teaming will not make you a better player, and in order to become better, you need to trust your own capabilities and develop skill individually.
Of course I am not saying that good players don't team, because that would be a lie. I know many amazing players who have become bored of the game itself and simply play for the community, hence teaming out of sheer boredom. I do not consider myself a 'great' player, I just feel as if I can relate to this topic very well.
Putting everything I just said aside, I am not having a go at anybody who teams frequently - as you probably have your reasons. Whether its out of playing the game for fun, or just chilling in a teamspeak.. xD
In the end we have all teamed before, so it really depends on how you look at MCSG; Are you here to become better, or to have fun?
That's my take on the topic, as you can see I feel quite strongly on this..
Great Idea for a thread, and if you read my whole post THANKS <3