I think it's just barely possible that there will be an equivalent to the FZ1000/2500, bringing the zoom out to 600mm - but we'd have to be very careful about the quality of the new lens. It's pretty hard to beat the FZ1000 for IQ, and it seems that lots of people have been disappointed with the sharpness of their 2500s.
The FZ 300 already goes out to 360mm, which is pretty nice, and people who have a good copy are getting excellent images. The constant f2.8 lens is a big help there.
I doubt very much that there will be anything like a longer zoom in an TZ200, which goes out to 250mm. It seems that there are people who are getting excellent results with the TZ200, but the DPR review is discouraging, and some users report less than ideal results. Maybe Panasonic is having some quality control problems which they need to work on before introducing a new and innovative camera.
Of course, if you want superzoom, you'll have to consider the Nikon P900 or P1000.
Bill
The OP was looking for a TZ/ZS, not an FZ, but yes 360mm out of a 1" sensor is at it's limits for now, until computational photography ups its game in cameras and that won't be too long I suspect.
The TZ200 goes from 24mm x15 = 360mm, not 250mm. It's predecessor, the TZ100 went 25-250mm.
The DPR review of the TZ200 is, quite frankly B.S., nothing less.
It's a great camera as my many posts of images from it will verify. Apparently it has a "soft" lens but there isn't a lot wrong with mine or many of the other Panasonics I've had in recent years. I did have a duff TZ70 (ish), off the refurb shop in the UK a couple if years back, but it was refunded instantly when I returned it, so fair do's Panasonic UK.
Marketing is more cunning than most naive and gullible, pixel peeping individuals lurking on this forum realise and it is a finely tuned art. There is a lot more mileage and marketing bang for the buck generated by a relatively small sum of money placed in greasy palms to enable a bad review of an enthusiast camera on an enthusiast website, than a zillion prime time TV adverts at a cost of millions of pounds. Anyone who doesn't realise that is as thick as a brick.
Dave