Suggestions for Rammus E's secondary effect?

Now, if any of you have went up against a Rammus before, you know pretty much everything about his kit. He gets to:

• Roll around really fast (Q)
• Gain tons of resistances for 6s (W)
• Taunt a guy for 1.25-2.25s (E)
• Deal damage around him for 8s (R)

What most of you probably don't know is that Rammus' E has an extra effect: Reduce the target's armor by 5/10/15/20/25. It's actually the reason why the name of the ability is Puncturing Taunt, and not just Taunt.

Contextually, this might make sense. Taunting someone "into a reckless assault against Rammus" would make them forget about defending themselves, thus lowering their armor.

However, gameplay-wise, this thematic doesn't synergize all too well with Rammus, and not so well with anybody that's not a bursty AD (it only lasts 1.25s-2.25s!). So I'm asking you, the community, if you have any suggestions for Rammus E's secondary effect!

Some ideas I've had:

1. Make the armor reduction last longer, maybe 3/3.5/4/4.5/5s? This way, Rammus himself can actually use the effect to his own benefit.
2. Change it to "Increases damage taken by the target by 5/7/9/11/13%". This way, the window of opportunity to focus the weakened target is not limited to only AD champions.
3. Add another effect: "If the target is a monster, increase damage taken by XX%". Many of the buffs Rammus received over time has been to "Help the little guy out with his clears". This could be another one of those buffs.
4. Remove the secondary effect altogether, and allocate the power to somewhere else in his kit.