Performance - currently, loading the simple list of textures with widths and sizes is prohibitively slow - this should be improved in two areas:
Improve the speed of the VPK loader (possibly by loading chunks sequentially, reducing disk seek)
Don't load texture sizes until they are actually needed - this should significantly reduce map load times for all engines. Loading the simple list of texture names should be quite fast.
VMT - VMT is a reasonably complex scripting language of its own (see Material Proxies). Need to add support for loading up basic VMTs as well as blend textures. Look into implementing the the material proxies at a later time.
This issue will track implementation of VTF textures.