I'd agree, JoB, on the timing.
Whenever someone leaves the fandom, we wish them well despite our sadness at our loss. As the creator Minna's a more crucial cog, but we just have to wish her well with moving her life forward to where *she* needs it to go. (And hope that that direction is not damaging to others despite our fears.)
We have rich headcanons about what happened before, and what happens next. I think it's best to pursue those ourselves. After all, pushing Minna to explain what her assumptions were surrounding what happened before ...didn't work out very well for any of us, did it?
We as a fandom have collective knowledge in a huge range of fields, and that was something that made it very fun for us to hang around and learn from one another. Minna didn't have that, she was just in it to draw her OCs having a cool adventure, and that took all of her time and then some. I wish that she could have learnt alongside us and incorporated those learnings, but it didn't work out that way.