Has there been any explanation from FDev as to why Tionisla still isn’t in-game?

[moorison]

Speaking of which, it's be nice if we had the Dodo station there too, and perhaps in a multitude of other places in the galaxy. Just for variety.

I think the coriolis is more style and nostalgia over being practical or realistic too, so there is not really an excuse. Variety consists now of a station in a unique setting (planet/star background, color tinting) and at some point you get the feeling to have seen all. The assymetry of asteroid bases hides the fact a little better that all those rocks are the same shape too. They could be introduced as stations designed with the immunity to Thargoid devices in mind.