Would you gain much? No. From FZ200 to FZ80 you would gain a bit. If you want a leap in quality, you would have to buy a fz1000/tz200.
I was in the same dilemma and studied all the tz and fz series, along with canon sx series and sony hx series. The tiny sensor cameras are outdated today(exception: when you really need 30-50X optical zoom). If you have the fz200, keep using it. If you want a significant upgrade, a 1 inch sensor camera would be it.
I had the chance to get a fz1000 at a very low price but decided to go with a tz100 because it fits in a pocket, size was important. The zoom is the only limit with that camera, i get very good IQ even at 2X digital "intelligent" zoom, but at that point the quality is almost the same with what a tz80 would produce. Anyway, the tz100 is a keeper, wish i had the tz200 with 16x optical, but not a deal breaker for me(i casually photograph cats).
Don`t know what the macro performance is like on the fz200, i`m impressed with what the tz100 produces, with some minor image tweaks(-5 noise reduction, +1 sharpness, +1 saturation) . I imagine the tz80 is the same or even better.
In conclusion, my recommendation would be to skip on the fz80- unless you can get it at such a low price that getting wouldn`t pose any financial strain. You already have the fz200. You should also definitely try one of the 1 inch models if you can, there will be a noticeable increase in image quality. That being said, i have a sony hx30v from the same era as the fz200 and i`m still satisfied with the IQ and ease of use, but i suspect the panasonic is a bit more sluggish by comparison(i also had a tz25 and was very dissapointed with it, no comparison with either the hx30v or the tz100 from today).

No edit. Test image. Macro AF mode.

No edit. Test image, Macro zoom AF mode with 3X digital zoom.

Made a HDR from 1 jpeg for increased color saturation and contrast.

Full zoom+ 2X intelligent zoom. Added contrast and reduced brightness in jpeg.