Why font of life is a much better version of stoneborn pact

So far, I've seen points for and against font of life's powerlevel. Let's first off state the facts : -Font of life heals 5 + 1% of your max health per autoattack -Stoneborn pact heals 5 + 2.5 % of your max health over 2 seconds. It's actually 40% on-hit and 60% over time Aka 2+1% max health on-hit and 3 + 1.5% max health over time.

This is nice because it doesn't heavily favour autoattack based champs.

So far it seems fair. No why would I think font of life is broken and is the new ardent censer drain?

The on-hit has a slightly higher base value, health will be farmable with runes. But most of all... There's a simple reason stoneborn pact is underused nobody mentioned.

STONEBORN PACT IS HALVED ON RANGED CHAMPS. FONT OF LIFE ISN'T. All the calculations on stoneborn pact were flawed. Divide them by 2 as the guys that will abuse this are adc's. That and the fact it is on-hit makes font of life a hugely synergistic rune with high attack speed ad carries. Stoneborn pact was thought out to not be abused. To be balanced for melee/range. Font of life, not at all. Especially if we consider the ridiculous amounts of attack speed gained by précision tree, and the presence of lethal tempo.

On a 3k hp tank, font of life heals 35/autoattack. Similar values as drain ardent censer. Let's not imagine how bad this is on a tank toplane cho'gath using stoneplate (80 health/auto now,if not more?) using it for a lethal tempo kog'maw with uncapped attack speed.

Be careful. Runes that aren't thought out to not be abused WILL BE ABUSED by our dear adc's.

Ps: keep in mind font of life isn't even a keystone.