Turnwise would depend on the amount it would heal in the end. If its heals a huge amount, turnwise if often better, otherwise you could tend to overheal. It will tough always be different from Restoration, because it will always depends on your current HP and therefore also your vitality. Anyhow I think it should be stronger than Restoration in the long run. Restoration gets replaced by better heals probably, but this skill has no better version.
Why do you think, I said: It should be viable on its own and not be punishing if you don't want to multiclass the min-max?
It costs no AP and does not scale with Hydro or Int, but it costs HP therefore scales with CON and Vit and Necro. If its one turn or lasts several just matters in regard of the amount healed. A heal is always a heal if you don't go the First Aid row where the heal is secondary effect., but the basics are different from Restoration.
In DOS1 were 3 heals I think. The weakest was 3 turns, the second 2 turns and the third 1 turn if I remember correctly.
I'm not sure how the exact rules work, but sometimes I had the feeling, it does not matter what did the killing blow, if some was just affected by elemental he most likely turned into dust. So if you don't go full physical you could have a hard time. Also with the current AI, summons just get ignored as long there is player in reach, so the usefullness of summons as meat shields is questionable. We will have to watch how they will tweak the AI.