Yes, an officer should be required to see your vehicle driving to cite you with DWI because a person may simply want to sleep off their alcohol while in the front seat of their car. Also, some people have nowhere else to sleep. They should be allowed to lay down in their car.
An officer should be required to see your vehicle driving to cite you with dwi. Logically the offence is Driving while intoxicated. Therefore it is only reasonable that the person accused be caught in the act of driving, not sitting in the car or getting into it. The offence is not intent or thinking about doing something, it is actually doing it.
A vehicle driver can refuse to take a sobriety test. The police officer needs to have some reason for charging the driver with DWI. Without the officer actually seeing the erratic driving to have a reason to stop the driver. Another person may make false reports as revenge on innocent drivers.
If a person driving while under the influence has driven their vehicle into a location where it cannot be recovered it would be totally unreasonable for an officer to have to view the care before citing the offender. However, officers should exercise their common sense and be sure that the person they are citing really was driving before issuing them with anything.