Are you having issues playing on high/ultra? I play the game on high with my machine (i5-3550, 16GB RAM, Radeon 7950), but I am pretty sure we do push things harder than BF4 did. Ultra probably could use optimizations, but to be honest if it were up to me it'd not be as big of a priority given I think the game still looks absolutely stunning on high and there's more serious stuff to look at in the short term.
If you're still having serious performance issues with good hardware below high then it's something that would be more likely considered sooner.
I also have what I consider to be frame rate issues.
I'm playing with an i5-4670k, GTX 770, and 8GB of RAM. Despite this, the frame rate drops down to 30 when looking at certain things. For example, looking out the door when I first wake up in Haven is particularly terrible. I've also experienced this problem when standing in a cave, with absolutely nothing going on.
I have tested this on several different settings. As far as I can tell, if my settings are anything above medium, changing them does absolutely nothing. The automatic specs detection system within the game puts my rig at a bit above the high preset, so this is what I was playing on originally and where I first observed this issue. The Nvidia GeForce Experience tells me that my system should be able to play the game almost on ultra. I don't normally trust this software, but it is another data point. Turning the settings down to the high preset doesn't alleviate the issue at all. This is strange to me, because doing so also lowers several demanding settings. If I turn it down to medium the frame rate will sit at 55 when looking at this same group of NPCs.
I'm hesitant to say that it is my hardware for two reasons: two pieces of software are telling me that my system is up to snuff, and I have read posts from people with rigs more powerful than mine experiencing similar issues.
I believe I have ruled out the possibility that it is my RAM or VRAM. According to MSI Afterburner, I come nowhere near using all of my memory when looking at that particular scene.
This issue is occurring (and even worse in many cases) across a wide range of hardware. I can provide a link to a thread where the "terrible fps" discussion is occurring if necessary.
Thank you for all the time that you have already given to this thread.