This is my suggestion...
Lightning whip: This whip is fine, keep it the way it is.
Bloodlust whip: This whip is fine, keep it the way it is.
Icy whip: The special for this whip is nothing compared to the other whips. It only freezes for a mere 5 seconds, and is not very useful in a pk situation compared to other whips. My suggestion is that you increase the strength bonus by 3 or 4 and make it freeze for 15 seconds.
Now for the introduction of more whips...
Poison whip: This whip would have a 30% chance to hit for a melee damage hit and a poison damage hit. This poison would be as powerful, or more powerful than (p++). The strength bonus would be in between the Bloodlust and Icy whip's bonus.
Power whip: This whip would basically be the opposite of a Lightning whip. It would hit one tick slower than a normal whip (longsword speed) and have a heightened strength bonus, higher than the Icy whip's bonus. It would have a 30% chance to hit for 10% more damage.
Holy whip: This whip would have a 30% chance to restore prayer, like the Bloodlust whip restores hitpoints. This whip would have the same stats as the Bloodlust whip.
Actual special attacks..?
Maybe you can add ACTUAL special attacks triggered by using your special attack bar for the whips, alongside having the 30% effects?
All these specials would use 100% of your special attack bar.
Lightning whip: An attack that hits three times with all three combat styles, only with 50% less damage each hit.
Bloodlust whip: An attack that is 25% more accurate that heals double your hit.
Icy whip: An ice burst followed by an ice barrage. (Magic-based double hit)
Poison whip: 10 consecutive hits of poison in 10 seconds.
Power whip: 25% chance of hitting your max hit, otherwise it hits 25% of your max hit.
Holy whip: Reduces your opponent's prayer to zero and then hits for 25% more damage.