Would you prefer the mavic 2 or the phantom 5 were to come out?
Both, because I have not yet got a Mavic Mk1 and a Phantom Pro 4

I have P1, P2 , P3Adv. P4, Solo x 2 & Typhoon H
To me both Mavic and Pro4 is still an Mk1 stage.
Mavic is size wise and Pro4 is the 1" camera being something I hope DJI will improve.
Mavic size is small enough, I am hoping for Mk2 improvement, after all Mavic Mk1 is a new breed/platform.
I am amazed at Mavic size and capability, but Mk1 platform it is , I rather wait.
Pro4, its 4K60P video is not there yet. Let's hope Ambarella better video chip in 2017 can help.
Pro4 uses Amba H1
Inside the DJI Phantom 4 Pro
I want to see Amba H2
https://www.ambarella.com/products/flying-cameras#H2
Amba H2 should improve the 4K60p and it can do 60p in H265 too.
It can do 4K120fps , so I hope no more crappy line skipping 4K60p the Pro4 is doing now...for Pro5.
Next improvement I want to see for Pro5 or Mavic Mk2 is how like 3DR Solo "marry" its gimbal to the flight controller. 3DR Solo gimbal and flight controller are like 2-in-1 system where if the pilot is good with pre-programmed move or smart shots as they call it , the gimbal action is in line with the flight controller and not re-active to the flight controller. I don't know how to explain better, but if one own Solo and a seasoned video guy, they will know what I mean.
Me I like all these flying toys, but I need to slow down on the collection and jumping to only an Mk2 of any new DJI platform sounds reasonable.
My 2.5 cents.