Increasing the RAM would be pretty stupid as the majority of third parties would not take advantage of it due to PS4 staying at 8Gb..
Right now the system are comparable enough that it should be relatively easy to develop software that works on both (especially with PS4 development seemingly closer to PC), any move that makes it so that it is harder will not be welcome, especially something like RAM as the way it is the most often used is through graphic assets and having to develop graphic assets different based on the console is a lot of extra work..








