Hmm, depending on how basic they mean, that could be a good thing. I have heard from Muslim friends of mine that one of the reasons they can't take Christianity seriously is that everybody seems to want an exception for his particular church (because I had brought up that it's wrong to blame my church for the Crusades when that is primarily a Western church phenomenon). It seems to them, I suppose, that Christianity is too messy to be considered as a cohesive religion. So maybe this would do some good in dispelling that notion and showing that, yes, we really do have at least some basic commonalities of belief that don't vary.
Anything more than that and I'd be skeptical as to what the need is for having such disparate groups come together in the land that basically created the system by which we were set apart from one another (under the millet system, which is still in place in some ways, e.g., the restrictions on the respective Patriarchs of the Greeks and the Armenians in Turkey). Is this a testament to just how bad things have gotten in Turkey? I know the Syriacs are not so slowly disappearing (with help from the government vis-a-vis their confiscation of Dayro Mor Gabriel), though I don't know anything about the demographics of the Greeks or the Evangelicals. Maybe this is a way to try to soften Turkish society's stance towards its minorities. In which case, good, I guess. I would think that the government is the main problem, though. Erdogan is the devil's cabana boy.
I dunno. Turkey sucks.