Paul

I think if damage is scaled like this then the most powerful character will simply be the spellcaster, and mundanes will be ass out. Mages would be the rulers of a world with this mechanic behind it, or there would have to be a setting device to address this.

That was the problem with 1st edition. Unless you had a DM who would give you a +5 avenger and a girdle of giant strength, any mage of 4th circle or higher was gonna kick your ass if they wanted to. When you have spells like this, one of the first things a mage is gonna ask is what level spell can I cast to improve my to hit, and my armor class, ignore armor and also attack with touch spells at range. It might be cool to have hermetic magic instead of having a progression that is this steep just have a general rule where maybe it goes something this

1 1d4+1 / 1d2
2 1d6+2 / 1d4
3 2d4+3 / 2d4
4 2d8+4 / 2d6
5 3d6+5 / 3d4
6 4d6+6 / 3d6
7 4d8+7 / 4d6
8 6d8+8 / 4d8

knowing that the mage who is casting a 3d6+5 touch spell is capable of ignoring the opponents armor, damaging the opponents enurance, and doing all that from range while invisible. It might even be worth thinking of magic instead of attacking Hit Points rather went after endurance itself. Sure maybe some truly physical attacks, but I would have them suck and be more like the spell shatter, or even knock, but with a physical damage rating applied to them as a secondary power if used on a person, that way mages have a way to do hit point damage by casting spells, but not needing to memorize, something as boring as "the spell that does the most damage for that level". Maybe you'd even run into a guy with shatter memorized before he was 15th level.

How many Hp do you expect a 12th level fighter to have, how much would it be affected by a 5th circle spell to attack his endurace, and how likely would he be to survive an attack not just from a 5th circle spell, but also a 3rd. How many rounds would it take that 12th level fighter to kill a mage who has a 3rd circle protection spell up, and some magic item that gives him damage reduction equal breastplate, but doesn't make him as easy to hit as that.

Is this a low magic situation or high? I think for D&D to be run properly it should be high, or fighters would just loose. They have to get items, but then those items can be used by mages.....

Just some thoughts after work. I'd also get rid of save for half on area effect damage to hitpoint type spells. I think moving to the safer part in a fireball is retarded. In fast I'd limit a lot of what mages can do and get rid of saves for half.