Hi, everyone. Current/most recent head of the Christian faction here (not a Gothic Earth character, but plays adjacent to them).
I have mixed feelings about this proposal. As you might imagine, I've had the chance to interact with a pretty broad palette of GE characters--and not all of them Christians. (Some people just see the tabard and assume you're from GE too.) I've seen the great, the good, the unpleasant, and the very bad.
EXPERIENCE
If I can, I'd like to start by sharing my experience in hopes that it might illuminate my position. First, I will say that I very much disliked the idea of GE characters when I joined the server. When I discovered there was actually a Christian faction, I determined I would keep my interactions with them to a minimum. Only when Vandryn had no good RP path forward besides joining the Christians (it was one of the only sensible options for IC reasons I won't get into) did I have him join the faction. Even then, I planned for it to be closure by way of membership--I was going to end him after just a few weeks. But then I saw how fascinating some of the GE characters' RP and flavor was, so I decided to hang around for a bit . . . and a bit . . . and a bit . . . and now I somehow lead the group I joined with every intention of quitting right away.
All that's to say, in my time with the group--overall, with some notable exceptions--the characters have tried to be somewhat delicate with the concerns mentioned in the OP's post. (The real-world religions aspect is kind of impossible to get around, obviously, but even then, most [not all, but most] of the characters I've interacted with have tried to be delicate and keep the public proselytizing to a minimum--mainly when it comes up in the RP.) We have a zero-tolerance OOC policy against racism, sexism, homophobia, and the like. At least since I've had anything remotely resembling a leadership role, players in our group who choose to engage with these subjects IC know that they can receive coaching and reminders on how to handle them in a way that's not disruptive. We obviously don't encourage those themes, but if they're going to come up because of a character's background, it's best that they do without harm.
Even so, there are several players who've indicated to me that they're uncomfortable playing around the group. I can respect that. There are some players who hate the group or view it as an unwelcome presence or think that our RP is less valid or what-have-you. I can understand that too.
And yet, there are also players who critique that our characters aren't more racist or sexist or homophobic or xenophobic because it's not "historically accurate" or "true" enough. I've gotten or seen comments to the flavor of "Your half-elf should never have been able to become leader," "You shouldn't be ecumenical," "You shouldn't have women knights," "You shouldn't admit demi-humans," "Your demi-humans are a joke," "You can't have a woman in a leadership role," "Your RP is a joke," "You're half-a**ing everything," and "Have you even read the Bible?" All of this is extremely discouraging and can make playing very unfun. It baffles me that people want such negative themes to be so integral to the group for the sake of "total historical accuracy" (possibly forgetting completely that characters and people grow and change with their circumstances and may learn to set such entrenched viewpoints aside the longer they're in the mists).
That's a long-winded way of saying that Gothic Earth RP feels like a bit of a catch-22 situation. There are critics on both sides. I've met them.
POSITION
There have been some great GE characters across my time on the server--both inside and outside the faction. There have been some poor ones too. Owing to Vandryn's position, I have often been one of the first people they meet, and in some cases, I have to do quite a bit of coaching to remind them of the GE restrictions. Many times, the poorly executed, highly offensive, or caricaturish GE characters quit or disappear after a few days or weeks. That's for the best, in my opinion.
Having said that, it seems like the NCE offers an opportunity to make such characters because everyone knows that they're probably going to be throwaways that get closured or shelved at the end of the event. Maybe they feel like there's no point in doing a ton of research or backgrounding for someone who's not going to last for more than 10 days. I don't know, but it's unfortunate.
I would be in favor of increasing or improving expectations for GE characters, but I'm not sure an application is the best way to do that. As others have pointed out, it's already "hard mode"; I sense that adding an app would kill the character concept entirely for most players (especially given the number of GE characters who get shelved because their players underestimated the challenge).
What about adding an RP manifesto that explicitly lays out the expectations and responsibilities of a GE character? All players of GE characters would be required to read and agree to this upon character creation. I don't know if it's possible, but maybe even require a passcode á la the password mechanism that GE players must enter before their characters can move--and bury the passcode somewhere in the manifesto so they actually have to read that.
What about adding a forum section for GE characters and those who play adjacent to them? It could be a place to post resources, discuss RP aspects and subjects, and get help when uncertain. We have something like that in the Christian faction Discord, which has been handy from time to time. Not sure if there would be an easy way to require said GE players to join such a subforum, but if there is, it might be useful.
EDIT: And, of course, I want to clarify that I in no way support or endorse bigotry or themes that make others feel attacked or unwelcome. We're all here to have fun. While I don't fully agree with the OP's proposal, I do see and recognize the validity in the concerns that led to it.
Sorry for the book. Forgive any typos--typed on my phone, as usual.