I started shooting weddings in the mid 90's on a Canon L2 Hi8 camera, then an XL1, and then the JVC-DV500 and a Pany DVX100... and then the GH1.. I was in the dvxuser forum when Tester13 hacked the GH1 (I donated to the effort).. Back when everyone was all googly eyed for Canon DSLR's... I shot with the 7D (hated it compared to the GH1) the 5D variants. The Canon loyalists told me many times "That Panasonic shoots a "consumer" format!" then those same people bragged about getting the Canon C100 which shot... AVCHD! There comes a time when ease of use goes a long way.. You and I can spot the differences between a full frame DSLR and a GH4 but 99.9% of our clients couldn't... and your job is to give them what THEY want... Not what you want. Make life easier on yourself. You will appreciate it. I switched to Nikons because I do photography as well but I picked up a Sony AX100 and the Bluetooth wireless system as a C cam and I found myself reaching for that little camera more and more simply because it took less time to set up and I needed to "get the shot" faster. Clients won't be happy with pretty pictures if you miss the one scene they really wanted because you were setting up your rig... Now I'm looking at the LS3000 and the Panasonic HC-X1 for 4K at 60P. I have two clients this year asking for 4K delivery and I'm sure with $400 4K TVs at Walmart there will be a lot more asking for 4K delivery in the next year. I'm thinking the HC-X1 with the GH5 would be a good combination for shallow DOF when needed and ease of use. Low light? Who cares.. get some LED lights.. they are cheap and should be a part of every wedding videographers arsenal for reception footage.
Both cams also do 1080P at 120fps so there's your slow motion should you want it. It's a no-brainer IMHO.