Due process is key to the rule of law.

Civil forfeiture denies those whose property is taken due process because (very bizarrely) the inanimate objects, not the person, is charged with a crime.  

Even worse, charging an inanimate subject with a crime, does not even involve probable cause.

If, for example, you are stopped for allegedly "weaving" (i.e. a feeble excuse to pull someone over), then the officer can use the hypothesis that your watch, cash, jewelry, even your car were the proceeds of drug dealing because you can't immediately prove the contrary and seize whatever she wishes to seize.

Then you have to hire an attorney which the officer knows may well cost more than whatever it is that the police took.

If the police can build a reasonable case and convict someone, then that property which is the fruit of criminal activity should be seized.

Without a conviction, taking a citizen's property is just organized government theft facilitated by denying the right to due process.