[SUGGESTION] ZZ'Rot active should scale with gametime

Well, the title about sums it up.

Let's face it, the ZZ'Rot portals active is not the best in game skill. I would wager 50% of the players don't even know this item exists, and it's about 15% who have ever bought it. The stats are nice enough, but the active...

So, this item is what I almost always get with Soraka, rarely on Rammus. And it's fine, shouldn't be overpowered. But when do you actively use this? I can imagine 2 scenarios:

• at a siege
• at defending from superminions (so oyu don't have to be there)

The problem what I encountered is: The item is only powerful when you get it veeeery early on. No build has (or should have) this item in it's core, let alone among the first item. Which means you won't be getting it til maybe around 25-30 mins in. By that time, your voidspawns are maybe on par with minions, but a few minutes later, they become utterly useless again.

So it's effective usefulness is like a 10 minute window.

This would be solved if it would scale off time elapsed, and not from base armor and mr. Or maybe a bit of both?