In other words, at any rational "% of magic attack," It would actually hurt your ability to damage at low levels, and even at high levels, the impact would be very small. If you did 20% of magic attack, you'd have a skill that does 1700 damage for almost no cost (Base + 5 ticks of 200+).
I don't see a problem with that.
If that's shadowmage damage at 50, that would be fine..
My sorc does that now.
1200 base + 5 ticks of 100.
Granted it has a 30 second cool down.
I made the suggestion for DoT's increasing based off of magic attack after the first day of CBT, give or take a few hours...
Think about this.
Nox, the final boss we were given for CBT, had 1.5 million HP.
Does anything less than 200 damage a tick sound right for that?
Not in my opinion.
You could have it scale off of both your magic attack AND your level.
How about this?
Your magic attack divided by your level + the base damage of the DoT?
So, if you have 2000 magic attack at level 50, and the DoT is 70 per tick, it would be:
2000/50 = 40
40+ 70 = 110.
I expect you'll have more than 2k magic attack, but you understand the idea.
If paladins have 5k health at level 35, and can remove 3 debuffs/DoT's per spell cast....
Your DoT's end up doing little to no damage when only ticking for 70.
Also, at level 50, I expect those that focus health, could have close to a 10k healthpool.
a 200 damage tick, would be on the weak side....