Ignite needs some compensation buffs for the nerf to grievous wounds.

Grievous wounds is now 20% less effective (50% to 40%) and doesn't effect outside healing, such as from Soraka.

Early game a solo laner chugging an HP potion heals around 6 more hp during that ignite; a fairly small difference, but frequently the difference between a kill or not.

But more importantly, it removed the most important aspect of ignite's kill potential in duo lanes and team fights; the heal reduction from supports and allies with summoner heal.

Ignite is already crowded out as a summoner, why does it need to be even worse.