I indeed did not take into account tank ole action nor indirect mitigation, but nevertheless, healers have waay more tools than they are normally using.
As you pointed out, low cost st spells become obselete at higher levels, which leaves me the question why they aren't directly upgraded in the first place. But there's more than that
As for "green dps", isn't that the current situation anyway? Tanks are defacto blue dps, but no one is complaining
It's either this or raidwide "true living dead" every 10 seconds to make healers utilize their full kit