The bard has always been a bit of an unusual class. One thing, though, that I've really enjoyed about the bard is that they get
Exotic Weapon Proficiency (whip) for free.
However, after playing a bit in Pathfinder, I'm continually bewildered by how restrictive the whip is:
A whip deals no damage to any creature with an armor bonus of +1 or higher or a natural armor bonus of +3 or higher. The whip is treated as a melee weapon with 15-foot reach, though you don't threaten the area into which you can make an attack. In addition, unlike most other weapons with reach, you can use it against foes anywhere within your reach (including adjacent foes).
The rules are similar in D&D 3.5 / 3, if I recall correctly.
I understand that it is more of a strategic weapon, but in Pathfinder, they've made the whip a bit more useful in the sense that there are feats like Whip Mastery (No longer provoke attacks of opportunity, deal lethal damage, remove armor restriction) and Improved Whip Mastery (Threaten natural reach + 5), but it still seems extremely restrictive (considering any other class would have had to have to be Proficient with the whip, and have
Weapon Focus (whip)).
In summary: effectively using the whip requires numerous feats, whips don't threaten, don't deal much damage (or any lethal damage), and provoke attacks of opportunity.
Why is the whip so restricted?