To both you guys up above could you kindly share sooc image of those as I really need see how they are as they sharpness on those beats mine sooc
I shoot with a very flat and boring profile with sharpness set to 0 in camera and then use unsharp mask in CNX2 or LR and don't need to do too much rather moderate settings as after fine tunes lenses are sharp to start with. Remember LR adds 25 as the Iintensity by default or as you configure irrespective of what you set in Camera. In CNX2 I use I - 35-45, R - 5 and T - 0.
The lenses you have are one of the sharpest on a D750 and if you are not getting sharp images, you need to fine tune them or you have a technique issue. A7RII is not going to solve that unless you are lucky to have perfect tuned lenses to begin with.
I can't tell you which camera will work for you, but with A7RII and good lenses like what you have now it won't be any lighter. An A7RII with the new 24-70 G master and 702002.8 G Master will weigh more than what you have. If you want light, go with prime irrespective of the system you choose.
I think a lot of people don't give enough time with what they have rather keep looking for a solution that doesn't solve on its own in buying something else. And after doing it few times, one may stick with a system not because the problem is solved, rather they realise they spend too much already achieving nothing.
You really need to decide what you want to shoot and if it is worth carrying the bulk of a 70-200 2.8 lens on any system. They are heavy, but what they produce is gold. I started with a Nikon 70-200 F4 fearing that the 2.8 will be heavy and ai won't like lugging it around and Internet supported my thought.
And then why I tried the Tamron my friend bought, I realised that a 2.8 produces something the F4 cannot. And believe me I have the 2.8 at least 5 times more than the F4 version and I don't mind taking it with me.
The D750 with a 24-85 VR is quite lightweight, So I don't see why weight could be an issue. A 35 F1.8 on a D750 is lighter and produces much better images.
I am sure Sony system will be excellent as these days it is difficult to buy a bad full frame system, but I won't discount the D750 for weight issue or sharpness issue as the problem lies elsewhere.
My 2 pence [emoji1]