Well, I still find the controls of Hg/Ss (permanent touch-screen menu options) easier to use. And the way it's all so colourful in comparison with the (understandably) darker Black and White makes me feel happy.
The graphics are still good, although the 3D bits do look horrendous (i.e. Olivine Lighthouse, although that looked bad compared to most of Gen III anyway), and the B/W graphics are better. Noises such as running water are much more obvious in Hg/Ss, which I like. Unique things such as pokémon following you, eyecatches, changeable pokémon due to daytime...they make me love Hg/Ss.
The seasons do set Black/White apart, however. Although I find winter just feels...wrong, most of the time.
One thing they have in common is the amazing amount of post-E4 activities :)
The only irritating thing about it is the horrendous lack of variety of pokémon until you have 2 badges (because after that you have access to everywhere between Route 29 and Route 36), but that's not something that makes it feel old...just makes me glad they did better with BW.