Everyone else have noticed the holes all over the HGV? Small rocket motors or pressurised gas to help with maneuvering and steering exo-atmosphere in usual cases like space capsules and shuttles. I don't think DF-17 goes exo-atm but these could help control the vehicle in hypersonic glide?
The first challenge faced in developing HGV is the glide part, like skipping stones off a water's surface. Controlling hypersonic flight is a remarkable achievement. Now I wonder which American or foreign system China copied off? I suppose those superior minds were generous enough to donate working samples and help Chinese figure out how it all works.
I haven't noticed, might have to take a better look. But if they were present then it would explain a lot of things, what I did notice was complete lack of control surface seams, those fins appears to be fixed aero surfaces, reaction control makes sense then.
Note that of all the maneuvering re-entry technology (good-ol reaction control, variable center of mass ...etc), none of them bothered with control surface, maybe thermal-protection challenge is too great to handle in such small package.
Another thing is the lack of seam between the booster and glider, I imagine them to be explosive bolt separation.
Conventional ballistic missile tend to fire at 45 degree to maximize range just like artillery, physics is the same. However HGV may have to launch at a much shallower angle in order to "skip" on the edge of atmosphere and not crashing down at 45 degree, so the launch vehicle might have to endure high speed in thick atmo for longer time.
Of cause all of the above oddities have a much simple explanation that they are mock ups...