We generally try to do exactly this kind of import coverage when there is a major game released in Japan way before it comes out in America. However, the length of time between JPN and USA versions is becoming shorter across the board, and since it usually takes longer to review a Japanese game, sometimes this is not worth doing because the English version could be out before we finish reviewing the Japanese version. There are also some other complicating factors such as acquisition of import games, language barriers, and interest in the game among our staff (particularly those with language skills).
So yes, it's a good idea...and we already do it. I'd like to do it more often, but there are some reasons why we don't.