It's been a very long time since I last touched Skyrim, and I did so on the PC, so I'm not sure of the crossover, but I was mainly using character customization stuff for new hairstyles, clothing, armour, etc. I probably overhauled the character textures and models at some point too just to get some of the clothes and armour to work properly, but I dunno if that level of alteration would be supported on the PS4.
I do remember adding a mod which made the civil war feel like more of a thing by adding randomized patrols and battles and stuff outside of towns. And I was playing pre-Hearthfire, so I remember trying a few player housing mods which basically became the inspiration for that DLC. One was even on an airship, but it couldn't fly around, it just kinda hovered.
I'd also recommend anything that adds more music, especially to the town and combat lists.