Please no. Healers are already incredibly homogenized. Removing everything the makes their playstyles distinct instead of working to solve the flaws introduced by what little diversity remains will only increase homogeneity.

Not every healer needs identical offensive kits and dots. Not every healer needs identical GCD healing spells. Not every healer needs identical cast times.

One or two good ideas, but they're so densely surrounded in homogenization that I'd stop healing entirely if all of these changes were introduced.