"If its not broken, dont fix it"
The biggest improvement is the graphics. Pokemon move freely which makes battle scenes feel smoother and more immersive. The story is different but in a good way. There are many challenges and side adventures to keep players busy for hours. Fans of the series will notice many minor additions such as pokemarts and Pokemon centers are merged in one and the breeder will inform you when your Pokemon make an egg. There are also 2 different types of battles. First there are triple battles where you and your opponent use three Pokemon to fight each other. There are also "Rotation" battles where you send out three Pokemon but only battle with one and thus rotate between the three Pokemon you want to battle. It sounds confusing but is very fun.
If you have never played Pokemon before I highly recommend giving it a try. It truly is an addictive r.p.g and in my opinion one of the best. Whether you want to catch all 649 or train an unbeatable team, you will have fun with Pokemon White and Black versions. I also recommend this game to fans of the series. Minor and major improvements to the formula make this Pokemon game an adventure worth taking.
PROS- Graphical improvements, addition of cool looking and powerful Pokemon, at least 50 plus hours of gameplay, tm's are unlimited, new battle modes, 643 Pokemon to catch and train.
CONS- Some elements will seem repetitive to seasoned players, EV and IVs still are not explained in full ( Although i understand them, i wished they had a visible list in which you can easily see the Ev's and Iv's your Pokemon has).