I thought part of the issue was that they changed the default from on to off. That, combined with the fact that badges cannot be awarded retroactively, meant that the wiki creator missed the trigger to get the badge. I could be wrong but that was my impression of what the issue was.
Does this mean there will be further improvements to Achievements or am I being to optimistic?
The achievements fix is mostly a side effect of another fix (one that wasn't user-facing) - it shouldn't be taken as implying significant work is coming, sorry. However, it's still nice to get it sorted!