You want know what I fear, With the extra engines people have on offer, Mark feels less in need to finish his
I agree entirely and feel that that is a strong argument to make for improving the language itself (i.e. add multi-threading, generics, closures, etc).
BMax's strength lies in it's modularity and it's ability to interface with outside code. There are already a # of decent 3D engines to choose from. There aren't all that many game-oriented languages to choose from. If you include C# in that list though, Bmax has some serious competition. I think Mark's time would better be spent making the language standout.