There's still a lot of cross-over between the two.
What I think would be helpful is if you could add an icon next to a topic when creating it to indicate whether it's specific to PC/Mac, PS4 or Xbox. If it's universal (like a lore discussion) you can leave it blank or add a symbol for that too.
If ZOS can crack down on the LFG and bite/trade threads, then it really isn't necessary. The game itself is the same, so using the same forums makes sense.