Lack of customization options and poor performance would be my top two reasons why it's trash, stock Android is better, Blur is better, *any* aftermarket launcher that I have ever seen is better. The launcher videos just show options you can do, I posted screenshots for some different types of setups you can do, fairly easily.
That's, odd. I ran it on a GS1 for a while and it was smoother then stock, obviously on a GS3 it runs like butter. Never actually tried it on a GS2 before, seems odd that it would run worse then on a GS1, but I've seen stranger things.
No sense of humor I know some of the Android users on this forum won't pay for anything, so I give them crap on occasion.
Nova isn't bad, certainly worlds better then TW. When comparing one of the premium launchers to the 3D ones I think you can make an argument that some of the features of the 3D ones are just showy, compared to any of the stock builds though any decent aftermarket launcher makes them look like crap.
Some of it you can't see, the various motion controls for different finger swipes, although anyone who uses CM is probably used to those, some of the gallery and music player functions are greatly improved along with the notes and calender widgets/interface.
Jellybean's default launcher falls under that category