Striking? Val
Wrestling? Could argue either, so if you say Val, I won't argue with you.
Ground? Weili has shown more in her fights against Suarez and Lemos than Val has on the ground. Val has the crucifix and good control, but Weili has shown a bigger bag so to speak.
Clinch? Val's certainly more credentialled, but I've seen more from Weili in the UFC (apart from a few nice trips).
Speed? Both fresh, I still think Val's throws faster single strikes (punches, kicks). However, I think Weili's almost certainly has better reaction time right now. I also think Weili would be faster in a scramble.
Overall, Val is the more skilled fighter, IMO. However, I'm not convinced she's better across the board, though. And even if there is a skill gap on the ground (favouring Weili), to the extent Val's stronger, it could be indiscernible/neutralized anyway.