I thought the DS4 was going to be forwards compatible anyway. So although it would be nice for the DSense to be able to replicate all of DS4's features (and I'm sure it will mostly), it's not strictly necessary. I personally don't think there will be any light tracking on the DSense so for PS4 VR games that use a controller you'll need a DS4. Then again, as has been pointed out multiple times, we haven't seen the back properly (which I keep forgetting).Any feature present in the DS4 should also be found in the DualSense, because the PS5 is officially back-compatible with the PS4.
Gyroscope will be there, for sure, and I wouldn't be surprised the new controller will also bleed sufficient light from its back for the VR tracking to be functional, too (although not evident from published pictures).