As with Mana Disruption disintegrate is not modified by lores and this makes it lag behind out attack spells at higher levels, as well as go against what appears to be the design goal if GS4 in that all spells are modified by lore in one way or another.
I think, if anything, disintegrate should be modified by necromancy, it isn’t a perfect fit, but it is a fit. The other option would be to use mana controls (an aggregate sum).
Many do not remember slate wands, but they had really interesting messaging. They would shoot a laser-like dull grey beam at the target and vaporize off strips of flesh. The crit messaging was fantastic, but the damage was erratic.
Still, it very much seemed like an aimed attack, despite being CS based, and I always thought it could be resurrected as an AS based attack.
How to do this though without ruining the CS based attack? The new web, 118, gave the answer.
What if disintegrate cast from offensive stance became an AS based attack such as with web?
I would keep the laser-like messaging from the old slate wands for the AS based attack, and which would make one infer that the way to increase damage with the spell would not to be to shoot a wider beam, but rather to hold the beam on the target for longer. Every millisecond the beam is on the target would result in more damage.
So, I would change the CS version of the spell to be modified by necromancy or mana controls for an increase in power. The degree of which would be decided by GMs as per balance.
For the AS version I would park the initial damage factor akin to wizard’s airbolt or a little stronger. Then, I would not have the lore modify the damage at all, but rather have lore (or mana control) training result in a longer lasting beam, which for game purposes translates to multiple damage rolls of varying strengths.
I would still like for sorcerers to receive a stronger AS based attack spell in a higher spell slot, but I think changing 705 to be dual purpose would do a lot to provide for flexibility and diversity within the profession.