East Asians good at planning

This is already just patently false by painting with a huge brush. I live in Japan and I know plenty of people who are bad at planning. That said, Japanese society tends to value planning a lot and, because of strict work schedules, little time off, etc., people often do plan things way in advance.

I don't think kanji have anything to do with this. Korea doesn't use kanji (hanja) anymore in any regular way, so that would invalidate the theory.

There has been some debate about them being better at math because kanji for numbers are more straightforward, but I think that's been disproven IIRC.