On the Subject of Hard-to-Balance Items: Negative Stats

TL-DR: Some items like Rylai's and Aegis could have negative effects to make them less of a necessity.

I've seen a lot of posts recently referring to how some items (most notably Rylai's and Aegis ) are too universally useful for the skewed utility they provide for the team. They're far too useful to pass up on on many different champions almost regardless of the stats they give, until they are nerfed so heavily that nobody buys them, so even when they should be used situationally they aren't strong enough to warrant it.

One possible way I thought to mitigate their general strength would be to give some direct drawbacks to the items. For example:

Aura: UNIQUE – LEGION: Nearby allied units gain +10 magic resist. (1100 range)

could become:

Aura: UNIQUE – LEGION: Nearby allied units gain 10% magic resist and lose 5% armor. (1100 range)

This would mean that, against ad heavy teams, buying the item directly makes your team weaker. It also means that against a mixed damage team, considering your proximity to your team's Aegis-holder will let you most effectively tank damage. (It would also make it stronger on tanks because of percentages, but that's just my own balance idea).

As for Rylai's, you could have:

Passive: UNIQUE – ICY: Damaging abilities slow affected units based on their type:.....

become:

Passive: UNIQUE – ICY: Damaging abilities slow affected units based on their type:..... Passive: Frostbite: Move speed is reduced by 30 (applied after slows/speed ups).

This would make fighting with Rylai's a little less about just spraying you slows everywhere and a little bit more about stopping clingy targets from reaching you, as when they do you'll have a much harder time getting away than before. It also means that in chases, with either you running away or running someone down, you're at a significant disadvantage unless you land your spells... unless you buy other items to compensate such as luden's or boots of swiftness. And in teamfights, you'll be trading your own mobility and safety to enhance your teams damage potential.

Not saying this should be done for every item (that could get out of hand quite easily) but it might make people think a little more when buying these kinds of "situational" items.