That's the kind of problem that would be easier to be fixed if the full source code was available to you. Cameras (among other things) tend to be a binary blob. Reading the associated bug, it actually appears to be the GPU driver that is out of date there.
The fact there are very few complaints is testament to it being able to run 4.4+.
Typically in porting a device that hasn't been officially upgraded a replacement driver must be found that supports the new API calls. Often drivers from phones with similar hardware is pulled in, which obviously will never work quite too well. This was a big thing when going from 2.x->4,x as the camera interface changed massively.
Looking at the bug report, they expect that to be fixed when they move to CM12.