I play an OC in a rather confined role. My advice if you do go the route of creating an OC: make sure that you talk to those in the @org that you intend on joining at length. Make sure they're going to stick around, make sure that they're going to be available for play, make sure they're going to keep you involved. It's one thing to regularly remind people that you're willing to get involved, it's another for the olive branch to actually be extended. Mind, that doesn't mean that I'm unhappy with Arx. So far I'm loving the game. I just recognize that very specific choice for an OCs role, devoid of established family, and generally devoid of much beyond his little tower has limited my own options. It forces you to be far more proactive in your pursuit of role play, which is ultimately only half the battle while being everything one can do for the most part.
Staff on Arx has previously been pretty vocal that they don't wish to hold new players of a @roster character too closely to what a previous incarnation had going on. There's some liberty available for players to do what they wish with a character, within reason(I imagine). Like, if you decide your style doesn't mesh with Jim, then there's not a problem with your character becoming distant from Jim. I suspect that it's sweeping changes they want to avoid. The devout clergyman of the past 40 years suddenly deciding he wants to become a courtesan, or something. This segment is considerably shorter only because I have not played a @roster character yet, so I have less insight there.