Though it's not a timemage I can see skills that are working somewhat like that. Like a spell that start's as a HoT and can be "activated" so it unleashes the rest of his healing power with a bonus on the target - or a skill that simply stops dmg and heal on target for a couple of seconds an then unleasesh both of it (with a healing bonus).

On the other side I was already completely wrong with my assumptions on the Gun(blade)er. So who knows?