I do not think it is easy to persuade @theymos to add a new board, because it means more spam, and therefore more work for mods, or adding more mods, so that is unlikely to happen.
It happened to our local board and when we suggest a new board for the lightning network
[1] [2], so unless you have a convincing reason and enough adoption/visits, I do not expect this to happen.
In short, adequate demand is the key to creating more boards? Can you give the number of topics that talk about Blockchain gaming?
Compared to the Lightning Network, quote the following:
Typically, new boards (child-boards) are created when there is adequate demand for them. Right now, I'm seeing five LN-related topics on the 1st page in Development & Technical Discussion, zero such topics on the 2nd page, four topics on the 3rd page, three on the 4th, and two on the 5th, and there are forty topics per every page. Post more LN-related content if you have something meaningful to say or ask, and in time a new child-board will be created.
[1]
https://bitcointalk.org/index.php?topic=5151200.msg51363546#msg51363546[2]
https://bitcointalk.org/index.php?topic=5209227.msg53333101#msg53333101