Orc culture or it's 'curse' is not an excuse, and most raids aren't exactly rp, it's pvp. You can still rp an orc without raiding. Either way, I don't like this change, pvp default will still be my favorite.
If you decide to keep this, at least change it so that if there is more that 5 people involved in the fight the default would be PVP unless both sides agree to RP or rollplay :-d
The problem with this is that rp takes such a long time, and banditry(remember aegis? Pay road tax now please) is often around public places. And more and more people will get involved. And it's very hard to say if the attacked player is asking his friends to 'pass by' on skype or TS. This is the main reason most people who do banditry and combat rp choose PVP over RP.