The main reason arch viles can take a while to kill is due to what they can do. If they're dropped into a room of dead enemies and are given time to revive them, you have to plow through those enemies again to get to the arch vile. Killing them quickly is definitely the best choice.
Now it's a routine to kill archies. Before, anyone had been scared the first time that saw the archvile and his attacks and insane speed. Now, you know that's the first priority to kill before any monster.