First off I don't think we need scent to be honest...
As of right now we have the ability to be able to track with our Sounds and Sight. If you ever look at the ground we all leave footprints behind. Its just not easy or as easy as we want it to be seen.
-I think instead of having scent we should have the footprints that dinos leave behind darkened a bit more. So we can actually track them.
It would bring all of the tracking together and not be as easy as seeing marks everywhere . You would have to listen, track and spot / track, listen and spot ect.
-If players want a bit more you can always just add a sniffing animation to trigger the footprints to get darkened.