The sense I got from the Erik Sondoval-Groell character is that he's a genuinely competent leader who has demonstrated his worthiness for command and legitimately believes he would better lead and safeguard the Federated Suns that it current First Prince, and you could make an argument in that direction, given Julian's impromptu execution of a prominent POW, and his chosen priorities. However, while Julian may not do everything as Erik would, his decisions have ultimately moved the Federated Suns in the right direction. I think that is where Erik's tragic flaw (ambition) is getting in his way, as the only path he really has to the throne on New Avalon is the civil war he claims (in his head) that he wants to avoid, and I don't see any evidence that Julian's leadership is so abysmal, that replacing it with Erik's would be worth the damage of another civil war at this point. You might suspect Julian of being a 6-7 out of 10 on the leadership skill, where Erik might be an 8-9, but he hasn't done anything to suggest he's actually incompetent. Erik was certainly willing to suffer Caleb's leadership, when it benefitted his ambitions, and I think that ambition is the driving force behind his decisions.
That said, there seems to be a profound tendency in the Federated Suns leadership and public, as described in Shattered Fortress and Divided Dominion, interpret Julian's actions in the worst light possible, and while you're never going to satisfy all the people all of the time, this sort of tendency may be getting some help from a directive source. Erik would be an obvious choice, but that seems inconsistent with his own internal monologue during Damocles Sanction. Gavin is introduced as a possible player, though promoting conflict between Erik and Julian would seem to be counter to his apparent desire to preserve the Federated Suns, within the constraints of our current knowledge.
I do think that the Old and Mercenary Nobility will represent a significant point of fracture in the near future. I'd really like to get some kind of narrative view into Bernard Marsin's plans and thinking, because right now he seems to be acting the role of the perfectly steady retainer in a time of upheaval. Dominions Divided seems to suggest Alex Hasek has begun to grow up, which is much at odds with his behavior in his final scene of Damocles Sanction, so I'm curious where that will go as well.
