An utterly brilliant game, just not a Pokémon game.
First off, I'd like to say something positive. I think Black and White had great graphics. They were original, new and cool (not as stunning as the trailers made them out to be, but still great). Furthermore, the battle style was way better than those of previous gens (minus the blurry backgrounds and pixellated back sprites). It felt more alive, and the move animations were pretty well done. It also made it seem as if the Pokémon were living creatures, rather than battle drones. In addition to this, there were several new features such as the Entralink and the Dream World that kept me entertained (even if it only was for a few hours, Sinnoh's underground was even worse).
Now for the negatives. As I said earlier, the reason I dislike Black and White is because I feel they don't have the same 'go on an epic Pokémon journey to become a Pokémon Master' feel to them. One of the most major things that contributed to this was the plot of the game. The whole story of the game was extremely poor. Not only was there a weird evil team, but the legendaries were completely unimaginative. Lugia and Ho-oh ruled the seas and the skies, Groudon and Kyogre, the land and the ocean, and Dialga and Palkia, time and space. Reshiram and Zekrom, truth and ideals, what on earth is that all about? Honestly, this is one of the many ways that Black and White break the running theme that has been used in every other game. Furthermore, what did they actually do? What was the purpose of Team Plasma controlling them? How would that help them to 'liberate' Pokémon around the world anyway? or help N to create his 'ideal world'? I also disliked the whole theme of Team Plasma. Not only does the name Plasma not relate to Yin and Yang or Dragons in any way whatsoever, but why did they dress like knights, and live in an underground castle? That's pretty odd for (what appears to be) the most technologically advanced region we know of (I know Team Galactic's dress code was stupid too, but at least they had a sensible name and HQ). The fact that their leader wasn't a middle aged man, who didn't reveal his identity until practically the end of the game, kind of broke the theme as well. I didn't really like that.
I would also like to point out that the whole style of the game broke the theme as well. No longer were you a ten year old child who receives a starter and Pokédex from a Professor and goes on a journey to become a Pokémon champion. You are now a 16 year old who receives a starter and Pokédex from a Professor who goes on a quest to vanquish Team Plasma. You even battle the evil Team Leader before you have your first badge. In fact, if you compare the blurbs of HeartGold and Black, you can really see the difference. Heartgold starts off as: 'Explore the Johto region as you catch, train and battle, with your favourite Pokémon by your side.' whereas Black starts of as: 'What are the true motives of Team Plasma and the mysterious N?'. Which do you think is better? -_- It makes the evil team more important than the catching, battling and getting gym badges, when it should be the other way around. It eventually got to the point where your final battle was with the evil team leader and not the champion, which was wrong.
Also, the Unova region was very bland and unimaginative when you compare it to other regions. There were no routes that branched off of the main path you had to follow, which made the region very boring, and there were only 6 HMs which you could use to explore. Take away fly and dive as they weren't really used for exploring, and then take away strength as that was only really used as a shortcut back to cave entrances, and you only have surf, waterfall and cut. The region shape was very bad too, and there were only 18 routes, some of which weren't really routes at all e.g route 18 and route 5 (However, there were some routes like this in Kanto). The fact that the region was hexagon-shaped and you could only go clockwise around it was very bad, as there was no backtracking, so you never really got the satisfaction of finally being able to go somewhere that had been blocked of when you first went there, and by this I mean whole new cities and areas, not just a cave, some trainers, or an item. There are also many minor things that make the whole game feel very boring and not as explorable, fun and interactive compared to the other games, such as not being able to grow and harvest a particular fruit; not having a Pokémon that blocks a path that you can move later in the game (Snorlax, Sudowoodo, Kecleon, Psyduck) ; not having a Safari Zone; not having a battle facility after the elite four; poison not hurting you outside of battle; random doctors and nurses that heal you so there's no need to buy potions; TMs being usable more than once so they aren't as special; not being able to battle gym leaders again - the list goes on. The musicals were very boring too.
Similarly to the musical, many other new features were boring or underused, but were highly overrated. For example, triple and rotational battles were only used around four times in the games, and their wasn't even a triple or rotational line on the battle subway, but there was such an epic build up to them. The same goes for the Castelia City camera, and the C-Gear, which has been dragged out for far to long with all these special Dream World Events.
Pokémon black and White are great games, if you like the new features, graphics and battle style, but they just aren't the true explore, catch-em-all and be a Pokémon Master Pokémon games. In fact, I know of several people who have sold their copies of Black and White because they felt the same way. Personally, I think that Game Freak have lost the motivation and imagination that inspired them to make the older games (In the Game Freak building in the game, the Planner is a fat old guy and is referred to as a Snorlax, which may be a message), and are now just doing it because they either want more money, or they are trying to start afresh. Either way, I feel Black and White were good games, but they lack that great feeling you get when you obtain a ribbon, find a rare Pokémon in the Safari Zone, or finally achieve your dream of becoming a Pokémon Champion. They weren't Pokémon games.