BW/BW2 Should I trade over my Pokemon from White?

[Frost Mage]

So I recently got Black 2, but I've put about 200 hours into my White so far, and it's where all of my shinies, Pokedex entries, etc are. My question is, when I beat Black 2, should I transfer over some of my Pokemon to there so that I can use them to enjoy the expanded metagame? It's just that even though I don't try to catch 'em all, I have around 350 Pokedex entries and I'd rather build upon that then start over. Any thoughts?

 

[King Arceus]

It doesn't hurt anything to do it. You can always trade them back if you end up needing them again. You should train over some of your strongest though if you want to beat everything the game has to offer such as the PWT.

 

[Frezgle]

Since you want to build upon what you already have, I would transfer some, but not all. I would only trade over the ones you know you're going to use, plus maybe just a few extras. You never want all of your best Pokemon sitting on one game anyway for two reasons:
1. In case you want to replay the story (my torment with White2; having one of literally every species of Pokemon seemed like a cool idea, but it turned the game into an unrestartable brick basically).
2. In case you lose or damage a game past playability. I had all of my best Pokemon on White, all my shinies, stuff as far back as from Sapphire, etc. Aaaand my dog chewed it up one day.

 

[Drohn]

I agree with Frezgle on this point. You don't have to transfer all your Pokémon. Trade the ones you plan to use only, and leave the rest in the game you use most. If you do use your newer game a lot more, then it's up to you if you find it worthwhile to transfer all your Pokémon. I always enjoy having my Pokémon on my newest version, but you might want to transfer them all to X or Y in a few months, so it might not be worth the time at this point.

 

[xxashxx]

The easiest and fastest way to do this if you have 2 DS's is to transfer a box to your new game and then transfer back before moving to the next box and repeat until done. Transferring a box forwards and back takes about an hour barring any mistakes then it takes a bit longer XD.