I think a nice addition to the templar kit in terms of a support role would be the extension of the Sacred Ground passive for blocking to group members or allies.
"While standing in your own Cleansing Ritual, Rune Focus, or Rite of Passage area effects and for up to 4 seconds after leaving them you gain Minor Mending, increasing your healing done by 8%. Also increases the amount of damage you can block by 10% for the duration."
Even if the amount needs to be lowered for applying to allies/group, it would be a unique aid templars can bring to mitigate some of their loss of identity from hybridization rendering Minor Sorcery null as a group can choose to spec into weapon damage, Minor Intellect and Minor Endurance having the option to be sourced from wardens or nightblades, Major Maim from the ice staff taunt, as well as the more conveniently sourced minor breach coming with U37.
It would mesh well with their concept of a 'radiant protector' and bring something to the table that other classes can't offer thus increasing templar relevancy.