I wanted to respond to a valid concern of Brian's as well, from the other thread.
This is a legitimate danger. The answer is in those "good roleplayers" being aware of this, and doing what they can to be inclusive towards other players. Despite that I'm doing exactly what he posts about above, I know that that is my goal. I want to create something vibrant that stands as an example to other players, but also is inclusive towards other players and creates meaningful interactions. If you approach your goals with that mindset, you can do a lot of good.It can also be a group of the "best" (using the term loosely, but it does seem that there tends to be consensus favorites at times) roleplayers who come together to play a family or group. This doesn't upset power balances so much as it leads to these roleplayers, because of their ties as friends/relatives etc. spending most of their time together, and one of their primary role play focuses being to interact with each other. When this happens, since there is only so much time and attention to go around, other players, fringe players, new players, etc. get less interaction with this group. It leads to a feeling of cliquishness in the game, and often resentment. SoI has definitely had problems with people feeling like there are IG and OOC cliques in the past and it can divide the playerbase.
I'll use the Earmhyde in Angost as a positive example here. This was a clan that did not fit in with the rest of the sphere (because, they were basically criminals gang-pressed into military service to protect the town). They certainly had their own culture that was private, but their presence and interactions with the rest of the sphere were often very positive in creating meaningful conflict and stories. And, despite often having some of the stronger combat players in their clan, they never attempted to make a grab for power or step beyond the limitations set upon them, because they were designed the way that they were designed.
Addendum: I do think that a lot of the fears set forth by players like Throttle, et al, are immediately mitigated by the game having two spheres with vastly different play-styles.
The types of players who are all about grabbing power and lording (which certainly, IMO, has its place) are going to be much more likely to play in the orc sphere as that type of play is literally built into the culture.