It all depends on whether you want / need 2/3 of a FF sensor for video or a half of a micro 4/3 sensor.
The pansonic isn't realy half size of 4/3 at 4k it's the same width just not the same height.
Anyway since you asked.
Ok in all seriousness I want it all.
Or better put, I want the electronic camera companies (all of them) to stop fooling around.
1. Touch screen focus like the gh3, tracking focus that covers the full frame without hunting like the gh3/ gh4.
2. In camera stabilization like the olympus em-1
3. xlr inputs with a good preamp, and a module like the panasonic that does conversion to dng and proress, without having to add another $4,000 box.
4. All active lens mounts. Every dslr autofocus lens with an active adapter.
5. higher sensitivity that is above 1200, though I'll never need 400,000 iso.
6. A dslr form factor where you can put your eyes to the viewfinder, not stand back and view and lcd.
7. A base mirrorless camera and lens system that even with a separate body will track focus, tether and shoot detailed stills as well as a Canon 1dx.
8. An approved list of kit, something like RED where everything from matteboxes, cables, in and out boxes, are either offered or approved.
9. Built in NDs.
10. Fast lenses. None of this 2.8 stuff or f4 in fact everything in T stops so we know that nobody is fooling with us.
11. An upgradable sensor. I'm tired of tossing 2,3,4,5,6,7,8,9,10 grand cameras because somebody comes out with a new sensor.
12. Variable crops in the viewfinder. Not red lines, no custom tape, but wysiwyg. 16x9 (though not my favorite format) should be the standard at all frame rates, from 120 to 24, because 16x9 is the standard for the web where 99% get's played.
13. 4 channel, pre amped sound with (drum roll please) wireless mic reception on 4 frequencies. I'm tired of hanging stuff off the rig. This can be an add on adapter, but make it work with standard Seinhauser transmitters. I'm sure Seinhauser would step on board in a minute.
14. wireless HD out for HDMI client viewing. None of this ipad stuff that has a flaky wifi system, but real radio transmitter 2k out.
15. If your panasonic, or sony, make monitors dedicated for this (see #14). Jeez your trying to sell tv's make some production monitors that run of vlock, or anton bauer, are wireless and mount or handhold easily.
16. Once again, an approved list of third party rails, dovetails, arms, mounts. (see RED). I have cases of 15mm and 19mm rods and fittings that never seem to fit anything new, without buying more stuff that won't fit anything new in a year.
17. A standard dnx, proress or dng format with approved video cards for color grading. Walk into adobe, or someone and redesign a coloring plug in that works on a suite in the NLE timeline. No round tripping, no transcoding, no spinning wheels and graphic cards that will work with thunderbolt macs and don't require an 8x lane. I don't know how to do this but maybe 2 4x in a box, but something that speeds up grading and is more intuitive.
19. Most importantly a film like look. See RED and Arri. None of this over smooth 5d3 look or clumpy noise in the shadows.
20. All lenses should have the same front diameter to make lens changes fast.
21. FAST long lenses. We don't use them everyday, but a long lens gives huge importance to a piece, so how about a 200, 300, 400 and 600mm equivalent at f 2.8 constant.
22. Charge me for it. I don't expect everyone to have the same needs but as the needs change, so do the modules. I'm amazed that if I trick out a 5d3 or an gh3/4 I spend twice the money of "stuff" than I do on the camera. I thought the camera industry was in the dumpster, so partner with someone, turn a profit and get it on the shelfs.
23. Forget #19 being most important. Most important is have the basics on the shelf the moment you announce. Stop this let's announce something so the other guys don't get a sale and don't expect your users to be your beta testers.
24. Keep the camera lightweight. A dslr form factor that you build up and can't see through the viewfinder is silly. Make it tall, not long, like a big motor drive on the bottom.
A smaller form factor makes everything cost less, work faster, gives you more time to create.