I hope Sony continues that trend with the a7III. Don't need the resolution of the a7RIII, but everything else the camera has is great. Those features without the resolution would make the a7II a killer camera. Once you start approaching the $3k US range, I start considering other systems. But if the a7II comes out at $2200 or below, that will be an instant upgrade for me.
If they make an A7 III, I imagine it will be a similar upgrade as the A7R III. Same sensor and tech, but improved everything else. So pretty much a lower-resolution version of the A7R III.
That's assuming they even make it, of course. The A7R II is already down to around $2300 new and they may just let that be their new entry-point to full frame mirrorless, although I'm sure there is some demand for a lower resolution sensor that also has amazing auto-focus and maybe doesn't cost $4,500 new. I imagine the A7S III is next for them, though, as that one is in most of need of an upgrade. If they can get the auto-focus system and other battery/ergonomic improvements of the A7R III and add something like 4K/60 video with no crop, then they would have a huge winner on their hands.
The way I see it Sony pushes on tech specs, but lag really far behind when it comes to making their cameras fun to use. I don't exactly want to program 8 Fn buttons before I can get something that works. Especially when I'm trying something out in a store.
I've personally never understood the complaints about ease of use when it comes to Sony cameras. I guess it's all subjective, but to me, the Sony system makes sense. I've always played with Panasonic, Canon, Fuji, and Nikon systems. The only ones that I ever had trouble with operating was Nikon. It wasn't immediately intuitive to me at all, but I figured it out after a little while.
Yea I can't live without having dual SD cards but it always seems like a lower priority for Sony for whatever reason. I always say Sony push a lot on the tech front but the overall system is less balanced from usage point of view. MILC is still too expensive for my blood and it's not going to get better with basically a couple suppliers for the sensor and the amount of tech required to move forward. Not that I'm concerned since I have no interest to replace a dozen of lenses I love. Sure I can adapt them but why.
I think dual SD cards is the way forward for Sony. The A9 and now the A7R III have it, although their implementation is less than ideal (one UHS-I and one UHS-II slot). I assume that they will just manufacture that going forward on all of their bodies and eventually upgrade it to dual UHS-II in a later revision.
There's plenty of good reasons to go MILC + adapter. You can gain a lot of functionality that you may not have on other systems. Whether or not that functionality is needed or even attractive to you is another issue. If you are perfectly happy with what you have, I see zero reason to even consider anything else.
My D600 has two cards, that's entry level. I paid like 700 for that thing. The AF isn't hyper fab, but it's serviceable and the sensor is great, AF points are too center clustered though. I do think Sony over charges a bit. The A9 shouldn't be more than a D850.
Having just purchased the A9 (used for $3800, no tax), I feel like the price is justified at this very moment. If you care about what makes it a unique camera, there is truly no other option available in the full frame market.
The A7R III that comes out this month is Sony's competitor to the D850 and is priced accordingly.