Qorsk i don't disagree, i think a 2 minute debuff is just to limit any degeneracy involving hot swapping consumes or loading two different variants onto the bar, and i think the ms % is a bit higher than it needs to be, but i'd rather they keep it close to the chest for now and tune into a softer edge with the full release of the game.
more to your point, not only does the ms% increase as you level, but the efficiency decreases from ~ 1.25 at 12 to ~ 1.12 at 60, so i agree, it does feel quite strange that the spell gets worse as you progress, but it's mostly to account for the heavy wisdom coefficients present on our healing spells as well as the fact that they get more cost effective as you level. our revival line at max rank, for example, boasts a massive ~ 1.29 wisdom coefficient which translates to a hefty ~ 3.7 hpm at just 150 wisdom.
before this forum devolved into what it is now, i was (read: am) a big proponent of a stacking consume debuff that allowed you to maintain a relatively harmless debuff for low intensity play but ramped up to a higher debuff % if you were spamming consume every 8-30 seconds.
however, the more i've played with it the more comfortable i've gotten with the idea of being unhealable, and i think it's certainly in a more than playable state. overall, shaman power level is very good, and if there weren't so much vitriol and bad faith posting it would be nice to discuss mechanical improvements to the class to help build a stronger identity beyond JUST cannibalize, but here we are.