There are one or two "best places" in each game, i.e. areas with the highest level Pokemon. However you are right there are a few too many of these questions.
The Zweilous one for example isn't any different to the regular BW one, nor is any question about specific Pokemon or types - since most Pokemon should have multiple type moves they should be able to train in any place.
So we can definitely have one question for each set of games, but any new questions should be flagged as they are duplicates. I will check the questions you mentioned and hide/close the appropriate ones. Thanks.