Something I like about guilds like for example Ogres and SS is that they both promote RP in the way they are coded. Yes, it's great when players take up excellent RP on their own, but it's also really nice when you get a nudge in the right direction. For most players RP is hard, and if the code can help a bit, that's good I think. I don't mean just emotes now. Ogres and SS kind of "forces" players to be play their roles whether they want to or not. It may sound bad to force players, but I think for most it's very helpful tools in order to RP better.
There are other guilds who do this quite well too, but perhaps not as clear as the above mentioned guilds, with ogres as the most clear example. I mean, who can play an ogre without feeling a bit stupid themselves after awhile?:) Now, in most guilds a lot will always be up to the players themselves on how they want to RP their guild, but I don't think it's a bad thing to include some things to nudge people in the "right" direction. In guilds that have a very clear role to play at least. That is of course up to the guildmaster to decide, if they want "RP-enhancing" code, or want to leave the guild completely open for players to do what they want with.
Personally as a player I always liked guilds that helped you out a bit with the RP. And the knights are actually a good example of the opposite, as a long member of the knights guild myself, "back in the days", the coded abilities of the knights kind of worked AGAINST the RP of the knights. Block can definitely be argued if it's a knightly ability, but I am talking mainly about "mercy". It sure sounds like a good and knightly ability, but it was just far to easy to knock goodies out to steal their stuff. Now, this was of course not allowed by the conclave, but as soon as the conclave was not looking people did it anyway, turning knights into thieves because it was just too tempting and rewarding to use the ability the wrong way. Later it was changes so you lost prestige when knocking goodies out, but it's still a good example of an ability that just made RP-ing your role harder, instead of easier.
And it's not only goodies who have these issues of being tempted to do anti-RP stuff. For example, putting very good items for specific guilds on their own guild NPCs always gives the players a problem. It's soooo tempting to kill your own guild NPCs for the item, yet you know it's super-poor RP. DAs and Mages used to (not sure if they still do) kill their own NPCs in order to get the EQ they wanted. Then of course try to "hide it" with some kind of RP reason of the NPC needing punishment or something.
Obviously, a better way to enhance RP would instead be to put that extra good DA item on a knight NPC, and vice versa, instead of tempting players to kill off their own NPCs. Same goes for some killing grounds. Let's take the DA's "training on trolls" as an example. They are supposed to protect Neraka, but trolls are obviously too good XP to pass on, so some sort of RP reasons needs to be invented so they can kill them. There are other guilds who cant attack their own troops, why not extend that ability to the DA too? That would help their RP, instead of tempt them to break it. And I am just using DA as example here, there's plenty of similar things in other guilds.
So to summarize, yes, players decide how much they want to RP or not, and what to do with their character, but we as wizards can also help encourage RP overall in the game, and in guilds that have been designed to play a specific role in the game. I believe that is helpful both for the player trying to RP that role, and for the game as a whole, because I do think Genesis should be a game where RP is encouraged, but RP does not come natural for everyone and if the technical aspects of the game also tempt you to break your RP, it becomes even harder.
