"the primary drawback" is correct and usable in written English.
You can use it when referring to the main or biggest negative aspect of something. For example: The primary drawback of this new cell phone model is its short battery life.
The primary drawback is the same frustration known by many past owners: finding fuel.
The primary drawback to this method is that in some freezers the tubs can take up to 24 hours to be frozen solid before use.
In experimental animals, the primary drawback of reverse pharmacogenetic methods is the relatively slow temporal resolution, which is limited by the pharmacokinetics of drug delivery and clearance.
The primary drawback to this mixed configuration is that it requires both IRUs to be powered, which generates more heat in that region of the spacecraft.
The primary drawback to using separate criteria for evaluating different types of expert testimony is precisely the argument set forth by Merlyn Clark, that the predictability associated with a single standard will be sacrificed.
The primary drawback was that the number of the cationic peptides and the location at which these peptides were attached to a t-PA molecule could not be regulated by using the chemical conjugation method.
The primary drawbacks to relying on passwords are that people struggle to remember them and often reuse them, and companies must store them in central databases that are targeted by criminals.
For many years, the oil and gas industry were looking for an alternative method that could significantly reduce the primary drawbacks of using explosives.
The primary drawbacks of this method are high computational complexity and reduced throughput.
One of the primary drawbacks is the fault intolerance since MPI has no mechanism to handle faults.
Despite its advantages, the primary drawbacks to online learning are technical issues and student isolation.
