Whether it's a good or bad thing depends on your perspective on the issue. If you're a talented person and want to be involved in politics but cannot do so due to having too many above you or a bad stigma associated with your native alliance then creating a new alliance is a solid avenue towards filling that need. On the other hand if you're a die hard member of an alliance and you see a couple of your best and brightest leaving in the aftermath of a hard war then you'll be damaged by it and view it negatively.
What it boils down to is personal ambition and sense of ownership...everyone fancies themselves a King and better yet, a King of something they crafted. As evident by the number of alliances that crop up annually it doesn't matter if that throne sits on a major alliance or micro. Although from the perspective of someone whose had his fill on creating alliances I can say that most of them don't survive for the sheer fact that they don't reach the critical numbers of active membership needed... most take shape with a handful of people to drive things but 15 or more are needed to create a stable long term grouping.
Still it is nice to see new themes crop up and faces in positions to break the monogamy that older power players have on politics. So I don't mind it.