SCH macro troubles

[Wolf_Gang]

Because it's the most efficient use of those CDs. The whole purpose of AoE HoT's is to top a party off after heavy raid wide-damage the quickest and cheapest means possible while continuing to focus the tank. While Rouse, Fey Illumination and Whispering Dawn is pretty overkill the HoT is so potent that your fellow WHM can completely forgo using Medica/2 or Cure 3

Efficient? How? I can't think of any situation pre-coil2 that requires that strong of a HoT that doesn't immediately go to waste within 5 secs of casting it. Rouse + WD alone will produce the same result every single time.
The reality is, your partner WHM will continue to cast Medica II oblivious to whatever fancy buff you cast further adding to the over healing.

I much rather use Fey illum independently in situations where WD is not up. e.g. buffing a WHM's HoTs because yours are down.