I'm still using the AC160 as my main camera on a tripod for weddings and it still does the job very well.

I work mainly in 1080P at 50fps but have been looking at the Panasonic HC-X1 which is a similar camera to the AC160 but can record up to 4K 50/60fps but has a 1" sensor.

My question is...for those that might know, I still want to stay with 1080P delivery but would the HC-X1 shooting in HD give me a better image than the AC160?

I know the HC-X1 will always give me the option of 4K but at an HD level, is there much of a difference, especially when available light is a bit low?

Thanks for any advice you can give!

It's been a year now so you either have solved your question or are still using your AC160.
If you are still using your 160 and considering the HC-X1 my input is:
The X1 is discontinued but discounted now.
If you don't mind the increased file size, I would replace the AC160 with HC-X1 and record in UHD 50P, edit and deliver in 1080P as you like, but the UHD aquisition will allow you to crop in some in post which provides nice flexibility I find useful. And the exported 1080P file will be pristine coming from UHD source material.

The HC-X2 has recently been released and on paper looks to do everything the HC-X1 did (minus some codecs) but adding a number of improvements so it might be the way to go.
I have some HC-X1/ UX180 and am considering the X2 mainly for face autotracking and better LCD screen