As MT noted, the healing/inflicting spells use a different mechanic altogether, and I will discount them entirely.
Polar ray would be improved in the same way Disintegrate would. I think Searing Light and Melf's Acid Arrow also function as a ray (although currently invisible) and so would also be improved.
But again, how many of these spells are used often as offensive spells in a situation that would be degraded by having Touch AC implemented. Most of the listed spells are either buff/debuff spells. Anything that requires a caster to get up close and personal with a mob is something I don't even mem on my casters. How many of the rest of the list are ranged touch spells that are not rays?