I wish it had better documentation.
I wish it had better VGUI tools(VGUI Build Mod) on HUD would be nice, but a VGUI designing/coding tool would be amazing..
The SDK templete multiplayer needs built in lag compensated AI and lag compensated vehical support.(tired of doing this myself, and my limited skills in predection/interpolation )
New HLMV with more capabilities
Nice, featured stuidiomodel, not just a gui wrapper
more features in template mod
Would trade all of that for better documentation with an official Doxygen..