No really, why would we want DX9 instead of DX7
Current way to do any 3D is to use GPUs and their power as much as possble; Blitz is totally incapable of using any of that. Only faster CPU would make Blitz3D apps faster (boning etc)... but there's no support for multi-core CPUs either which is the the trend... so either way Blitz3D can use only fraction of any half-modern hardware power.
Blitz3D is a dinosaur, no matter how you look at it, as it doesn't fit into any hardware pipeline anymore. But it does not mean that you can't do god games with it; it's stable and reasonable fast and certainly easy to learn. You just can't do Crysis with it.