Replacing the internal HDD on a PS4 slim isn't that much of pain. Takes about 20 minutes to remove the drive from the PS4, remove the drive from the caddy (damn screws!), screw new drive into caddy, reinstall it on the PS4, plug in a USB 3.0 flash drive with the latest firmware (not the update; full 1GB firmware file), fire it up and follow the onscreen prompts. Once you're back into the XMB, reconfigure PSN to login, go to Library, and start reinstalling any digital games.
Dropping a $ 40 250GB Seagate SSD from Staples into my PS4 slim was the best thing I ever did.