Emerald and Platinum was a waste. Black and White 2 isn't.
Even if Emerald and Platinum contained brand new cool features such as the Battle Frontier and other areas, it would still be a waste, because you wasted your money on Ruby, Sapphire, Diamond, and/or Pearl, when you know that the third version is a "patched" version, so to say.
I remember in the early 2000's, with PC games, we just bought the content that was actually new, and not entire games + new content. Those were called expansion packs. And even fixes were given for free, but since Pokemon is a handheld franchise, I could understand that something like "patches" couldn't exist. For example, there are 8 multiplayer maps in Return to Castle Wolfenstein that you could have bought in 2001 when the game first came out. That was version 1.0. Then there are patches that added 2 free maps. Then they released a Game of the Year edition in 2003, which comes with 5 brand new maps, on top of the 8, so to say, it is the Emerald or Platinum version, and that version of RTCW was 1.33. The difference between Platinum in relation to Diamond and Pearl, and the GOTY edition in relation to RTCW, was that, you have to shell out a full game's worth of cash just to get the extra content, while to get the extra maps, you simply have to download the patch to upgrade 1.0 to 1.33 off the internet, provided you bought the original version. Then later on, the added another patch for RTCW to 1.4, and they released, a coincidence, Platinum edition of RTCW, which includes a free multiplayer stand alone game known as Enemy Territory with it. You need not buy the Platinum edition to play ET. You just need to patch RTCW to 1.4, and download ET, which is free anyway. Usually for console games in the early 2000's, the have to design it so that the entire game is complete, and that no mistakes are made, as you can't patch a console game, and it is similar to a Pokemon game. Oops, there is a bug in the Diamond version, but it is fixed in the Platinum version, but sorry, you have to buy the same game again.
I could see some arguments that "hey, Diamond and Platinum aren't the same, since they have this and that difference". Well, so is Madden on the 360 and PS3. One has a green A icon, and the other has a blue X in a black background.
So what they are doing with Black and White 2 is a huge leap forward. You are essentially not paying for the same game, and that if they try to enhance something, it would feel like an improvement, rather than a fix.