I've been playing Skyrim Special Edition and I have to say I greatly respect the improvements made.
I'm using the same computer that I used for the old version so I think I can make a good comparison.
The flowers do make Whiterun Hold look much less like a barren tundra though. Some will like that, others wont.
The actual city of Whiterun definately got improved since now most homes have flower planters in front of them.
Very few other things got changed but I have noticed many bugs got removed only to be replaced by new ones.
The God-rays got significantly improved in comparison to Fallout 4. (No longer pixelated and no longer lag inducing)
Obviously the graphics got improved. They are now comparable to some of the less over-the-top texture mods for the old game.
The lighting is leaps and bounds improved. It actually surpasses most mods since you don't get the effect of stupidly increased Darkness and light.
That's all I've got to say for now but I've only played 11 hours.