Mmm I don't disagree, but my outlook on healer is more... "they can all heal but do so differently". While the differing utility is nice, as you've mention we barely have fights where they would shine so while nice, I don't think it should be what we're aiming for.
To best explain it, lets use your Macrocosmos example. I don't see it as a utility to bypass a heal check. I see it more as AST is able to heal this better than the other healers in this situation due to how their heal works. And thus, I'd like the other healers to have something similar. (Further, rather than a compile heal I'd like for Macro to be more of a Rewind and perhaps give the compile aspect to WHM's Lily Bell but that gets really messy and diverts from the point).
That said, I do think it'd be nice for us to bring utility like Expedient.
Tangent aside, I agree that SGE could still not bring anything other than DPS. They don't need a party buff (a la Divination/Chain - PLEASE KEEP AOE KARDIA) and I can't say I'd like them to be the supportive healer. That fits WHM and AST a bit more (with SCH also being a bit more damage oriented but not quite as much as SGE).
/shrug
MP idea is above my head. Its something I'd have to play with and may require tweaks depending upon how MP heavy SGE is. Or healers for that matter (cause I assume most of these abilities would cost MP and not CD only which would be a nice change, mana management). And having unique ways of doing so - like Addersgall into MP or Ewer back (SE >> Do it). Perhaps something interesting for Thin Air for WHM and SCH is... above my paygrade. Just something different to SGE (unless it can stay the same, maybe something with Fae Gauge?).
Anyroad, these ideas are a start to a better SGE and hopefully we get that with 8.0.