You may love attacking with them but it still would make more sense to have a defensive bonus, for example they can't get the city raze promotions, which means you're unlikely to attack a city with them and need to make melee units for that, archers IMO are good as an escort to these units and as a defense in your forested elven borders. Well, except for Flurry.
I have to disagree. They may be an unconventional city attacker, but just cause they don't get the city raider promotion line doesn't make them an impossible choice when attacking a city.
They are the only class that can get the drill line, which is just excellent.
I would actually rather use them as the killers while using melee as the softeners. Or preferably Horsemen as the softeners with flanking II or III (so 15-25% would retreat).
And it could be argued that +1 defense on archery units could make them a wee bit too good on the defense. I like that they can use archery units more offensively. (And as I've said before, archer of leaves becomes 5/4 and archer 4/5 - making archer of leaves actually useful)