Echoes doesnt allow people to symbol of death / wail through content. Savants can throw their third level spell, AM can toss SLAs, and PM sla's cost HP + the aura is too much mana for echoes to cover.
Let them make a choice. Do they want melee + DOTs, or DC + DOTs. Giving them all 3 is insane.
Making tensers a viable spell is a great suggestion, but adding it on top of what casters can already do, rather than having them make a sacrifice for being able to have viable melee, is tossing the most powerful classes another bone.
More options is better, but that doesnt mean allowing them to have all options at the same time effective in the same build. Imagine divine power giving clerics their wisdon as a to-hit / damage stat. All I am asking for is that arcane make the same build choice with tensers as clerics and FvS make with divine power. They can either be melee + DOT, or DC + DOT, but not all 3.