i'm guessing you are referring to this thread:
http://www.conquerclub.com/forum/viewtopic.php?f=63&t=58624and this comment:
ZeakCytho wrote:oaktown wrote:That said, a little bird told me that you may be seeing yet another attempt at a japan map very soon. As in very soon. Exactly what era it will reflect could be open for discussion.
Is it just me, or has every recent idea of yours been preempted by someone else? Romania, Japan...it felt like there were more

I think what he meant by that was that Oaktown has recently been attempting to make a lot of maps that have already been tried (and failed) before then.
There is no problem with using an idea that has already been attempted. As long as the person that made it originally has stopped working on his own project, then you would be free to go for it.
Like, if I tried to make a map of Alaska.
If my attempt went badly and I quit working on it, you are free to take the idea and work on it yourself.