My speculation a few days ago about a possible successor to the FT-817/818 met with silence. I guess Yaesu is looking at ICOM, the KX2/3 and the Chinese and wondering if they should bother. If I was Yaesu, I'd be thinking twice.
They need to come out (if they do) with a "killer" QRP product that everyone wants with some very unique features.
On performance these last few years I have my doubts. They are capable of doing some excellent products, but seem to be floundering in recent years. At one time they were market leaders. Nowadays they are market followers trying to catch up.