I do think the addition of an optional reason field on the Xcards would be very useful, and I prefer it to the inclusion of additional cards. Keeping it simple keeps the threshold to use it low. Using a system like we have for other optional parentheticals makes it pretty easy to simply XCARD without having to puzzle over what to put in the "reason" field, but allowing you to XCARD (reason) can really help to remedy the various situations for which roomwide ooc is usually felt to be necessary. (I'm also one of those emphatically opposed to roomwide ooc.)
The one issue I've found with the use of green cards so far is that it can be a little ambiguous what they mean or how to proceed. Different possible uses of a green card might be "gotta go afk for a second, go on without me" in the middle of a busy scene where you don't want people to wait on you, versus "give me a minute to respond" because you're composing a wall of text, or need to think about what you're going to say, or want to fact check something on the wiki that your character should already know. Or maybe you just need people to slow down, they don't necessarily need to wait on you, but you're struggling to keep up and just need a slower pace. So being able to specify what you mean to express with your green card could really help.
This is slightly off-topic, but I'm going to say it anyway, because it's important to me and I don't know where else to say it. I personally want to encourage the liberal use of yellow cards at the first inkling of discomfort, and not feel like you should wait until there's a Problem (reserving red cards for a Crisis.) Sometimes when your hands are shaking during a tense scene, or something heartrending moves you to actual tears it can be cathartic, and exciting. But sometimes that IC-OOC bleedover is not fun, you as a player are feeling hurt, or nervous, and maybe you're struggling to tell if that other player means you any harm. I wish I could say "we're all friends here! you should just trust the other person" but we all know that griefers and trolls and bigots and bullies and various creeps will inevitably manage to slip through the cracks.
I'm one of those players who likes to play very interesting people, so sometimes I'll say or do something that wasn't very nice. I think conflict and friction, opposing agendas and complicated relationships can be fun, and make for good RP. I'm really not here to spoil anybody's breakfast cereal. To that end I need to be able to trust that other players will let me know if they're not having fun. Trying to mind-read whether that disapproving look was totally IC (and probably warranted!) or if the other player is trying to meta-communicate OOC discomfort is crazy-making, it causes good-natured but challenging roleplayers to back down, and leaves conflict the province of the trollishly inclined. And that's how CvC breaks down, which makes things very boring. So, yellow cards please! I don't want anyone to be having a bad time.
