Do you have a 500GB HDD on your ps4?
I'm about to upgrade my ps4 HDD to 2TB. I had my ps3 at 750MB, I think (maybe 1GB, but I sold it with that HDD in there, so I can't check). I have been ignoring ps4 since I have such limited room versus the 500GB X1 storage + the 2TB external (and I could add another external if I needed to). Not sure why Sony doesn't allow external for game data. Even if I could swap the games around so that the ones you play need to be on ps4 HDD, that would be ok, but I have a 250GB/month data cap & I only own about 5% of my PS4 games on disc, sadly, so I can't swap around games if it means redownloading them. At least deleting the game file doesn't delete the save like it does on the Vita, which is STUPID. You can use PS+ to get around it, but not if you have reached your cloud save limit, so that puzzles me, as well (it seems it was to force you to buy bigger cards instead of swapping 2 medium size cards out, because I can't think of any other reason this would make sense to Sony, even). The swap process takes so long, too (if you want to do full backup/restore or get everything exactly like it was before you upgraded...which means redownloading/reinstalling, changing settings, etc, if you opt for the faster method where everything is done separately).