And I'm not trying to defend A6.

You are asking good questions but, like most good questions, there are no easy answers.

There are reason that you would want 64-bit but, right now, most games don't take advantage of them. They will in the future, but not now. For now, 4GB is much larger than the memory footprint of any consumer game (few PC even have that much memory).

When more PC have 8GB or more memory, then 64-bit will become very important. If 3DGameStudio doesn't run pure 64-bit at that time, it should be at the top of the list.