Gonna start by saying the blue sky reminds me of the PV they put out when the VA logo got changed. Dunno why, you can’t glean much from a sky, but I suppose it’s the fact that it’s environmental.
I don’t think they’d want to retread Owari since each album in the series is supposed to have a unique identity, but an album of another kind would be believable imo.
There were other novels made as part of the Kinetic Novel brand between planetarian and Harmonia, although they weren’t made by Key. I wouldn’t say there’s a fixed limit on how many can be made in a certain timescale. I think those short-form novels will become more and more common as the native PC market gets weaker and the smartphone market becomes more desirable. It also makes sense because production time is shorter, and the less time you spend on getting a game made, the quicker you can put out new merch to sell.
Umiket wouldn’t be on this.