... and we are not having euivalent ram/cpu to meet reservation need
This is exactly the point. If there's a requirement for the reservation (either from a technical point of view or just for support requirements) and you cannot guarantee resources without reservations, you need to add more resources (memory and/or CPU).
Without reservations - in case of overcommitting resources - you may run into issues with the applications, although VMware does a pretty good job on resource handling and scheduling. Unless you are bound to support requirements, you could try to run the workloads without reservations and monitor usage and performance to see whether the reservations are really required (from the technical point of view).
André