Electivire is severely overrated. He's way too slow on his own and needs Speed support to sweep successfully. Once you know someone uses an Electivire, just watch out for a switch-in and counter it appropriately.
Thunderpunch/Ice Punch/Cross Chop/Earthquake beats Normal, Fire, Water, Grass, Ice, Electric, Dark, Steel, Dragon, Ground, Rock, Flying, and Poison. Choice Scarf with base 123 Attack is still pretty scary, and average Speed with a Choice Band or Life Orb can cause a lot of pain. If an Electivire gets in unscathed, it can cause some serious problems.
That being said, Speed does hold it back from being a staple, but it's still quite a good Pokemon.