So.. who's leveling a SCH?

[Madoka]

Medica 2 before - Aggro ripper, mostly overhealed and wasted healing
Medica 2 now - Far less Aggro generated, same healing, less chances of overhealing and wasted healing since it lasts longer with lets ticks per go.

You didn't lose any regen effect, it just trickles in slower and they made Cure 3 less crap so you can actually use it. It's more efficient than two medicas even without the procs. SCH cannot AoE heal the way you do and you changing to SCH won't make you a better healer.

Cad won't be throwing down enough damage in the next 15 seconds for Soil to outweigh the Lustrate heal.

That really depends on his stacks, as a Soil when the tank is out of CDs can mean another 10 seconds of the tank not dying. Cad is also a good example of spike damage., after you blow your aether you can't lustrate again until aetherflow is off CD. WHM can do heavier heals with cure II when needed and have less need of something like lustrate, which is why benediction is on a 5m CD.

It's good to keep soil up frequently, but you don't want it on CD when the spike damage is coming either