Any ideas of improvements from the GH4?

No official release date nor features for the GH5. Only speculation.

Any ideas of improvements from the GH4?

The actual releasedate and all improvements over the gh4 will be known as soon as Chris posts it in the Digital Video Industry News section of this forum, everything else you might hear or read in the meanwhile is just speculation and gossip.

"if not sooner"

Obviously ONLY Panasonic knows what the GH5 will be and when it will be released, but here's a list of "rumors" for most camera makes, including Panasonic;


The Most Exciting Camera Rumors of 2016 (http://www.premiumbeat.com/blog/the-most-exciting-camera-rumors-of-2016/)