I'd agree too much of our healing comes from smart heals (especially HST), but it does so for most other healers as well. The percentages people are claiming their HST totem is doing is likely due to not needing to perform to their full potential on a fight or on terribly designed encounters like Immerseus. The only time(10 man) HST is a top contributor is either when a fight is on farm, or on really spread out fights, the fights where we really shine HST likely won't be above 10% if you're playing the class to its potential and not running with too many healers. Dropping HST is a bit of a simplification of maximizing its potential unless you're just trying to snipe heal, it's by no means as interesting as managing ReM and Uplift but it's not much simpler than Wild Growth or Prayer of Mending, just on a longer CD.
On our first H Protectors kill which I've found to be the hardest to heal (2 healing) thus-far, HST was only 7.4% of my throughput, I don't think that's an excessive amount of healing from it considering the current state of the game for healers. Conversely on H Immerseus HST was 28.3%. I'd be more inclined to think inflated HST numbers are due to bad encounter design rather than class design; both of these cases are somewhat polar examples of spell use on encounters, but regardless, on the hard fights where it really matters player skill is equally important for a resto shaman as it is for any other healer.