I really do not get it why most people need a larger space. My PS4 cannot even reach half of my hard drive. I only play 1 game at a time with no updates and patch (Yes I played Assassin's creed unity without updating). I also (almost) never connected my PS4 on the internet, just first when I had to set up it and sometimes when I want to change my avatar and buy themes. I also don't get why people install and play multiple games.
Many store other stuff besides games like shows/music/ect.
they install multiple games because they have other people come over and play them.
I would suggest that rather than opening up and risking damage to the system, you should use external drives. You can get external ssd drives easily.
This was made before external was possible, but still its very easy and pretty much no risk in upgrading a PS4 storage.