I was happy to see they fixed the irritating, constant 'glitching' of cars and pedestrians in virtual Steelport, as that was grating in the original game.
Saints Row isn't really a game that relies on hyper realistic textures and facial capture and such, but the game will need a big overhaul by the time the next full title rolls around. Visually, particle effects are improved, but Saints Row still looks pretty dated compared to its competition like GTA V and Infamous: Second Son, particularly from modeling perspective. In short, not much, other than adding the two clumps of DLC.
Those six hours did give me an insight into what, if anything, Re-Elected changed about the vanilla game. I don't foresee this being a common problem, as I feel like I'm just an idiot, but a word of warning all the same.
As much as I might appreciate Saints Row 4, I cursed myself and really wanted those six hours back. It was only then that I looked at the box and realized that the Gat DLC was literally standalone, as in, there was a card in the box with a PSN download code for the expansion. Six hours later, given that the Johnny rescue is one of the game's later missions and I'm still distracted by sidequests and glowing code fragments, and there was still no Gat Out of Hell.