If a single is old/mature enough to get married, no matter what age, said single should not need his/her parents to decide whom he/she should go out with. Therefore, I agree, shadchunim should go straight to the single with any ideas.
If a single needs help “researching” his/her parents can help with that part. And of course, parents can be consulted with in between/after dates for some guidance b/c “love blinds.”