Apologies
if I didn't make myself clear, but it seems I didn't given both Amir's
comments. I am very happy that we have these, and my question was not why do we have them, but rather why do we only have 2.
I want more of them and every time I've asked why we don't have more,
I've been told it's a community decision and that seems odd to me.
It's a community decision in the sense that it wasn't something the WMF decided for them, it was those communities decided it for themselves. They're open to it probably as a result of being generally less conservative when it comes to changes, and more willing to try things out early. But, it's not a community decision in the sense that you, as staff, can't get involved and try to recruit more wikis!
So, if other wikis are asked if they want to be in group 1, understand the advantages and disadvantages of that, and they said yes, I doubt anyone would raise any objections. Having more wikis in that group to test things on early would definitely be a benefit.
Amir's suggestion to contact wikis that have been open to Growth features, like Czech and Korean (I think?), sounds like a great one, especially if there are community ambassadors that could help explain what it means to be in group 1.
Dan