I think you're exactly right that Moffat is actively trying to be better at diverse writing and casting, and that he's open to acknowledging when he's messed up on these issues in the past. I had basically the exact same argument you're having when I posted his recent DWM interview on Facebook a few weeks ago and got told that Moffat "doesn't deserve a cookie for doing the bare minimum." Like, nobody is saying he's perfect, but why shouldn't we celebrate when people improve?
I agree. I mean, if people aren’t given the space to screw up and strive to improve, it’s pretty much impossible to progress. I’d love everyone to get things right first try, but it’s not really something that tends to happen. Encouraging and celebrating improvement, though, that does cause change, as has been pretty clearly present in the evolution of diversity focus in Moffat’s era of Who.