Many arcane spells are so bad its hard to comprehend
I only have access to all of the spell data on the wiki, so if that's inaccurate some of my comments will not apply. It's no wonder why people aren't playing wizard and sorcerer very much. This is because most of the spells are extremely bad and beyond useless.
Right now there are like maybe 5 or 6 decent arcane spells. This severely limits the options available for casters, especially late game, where the only role for a sorcerer is dispelling and wizard (rip) is just a guy with books and tall tales. Most of these issues are also relevant for invokers (press F)
If I had access to the code I would submit changes, but alas, I am not a team member.
There are 2 main issues with the current spell selection:
Some spells are just worse than other spells on their level, ie Summon VII vs Mord's Sword, worse than that, some spells are worse then spells several levels lower than them Cone of cold vs fireball
There is no way to overcome energy resistances, so in addition to doing less total damage, what damage done is soaked up by elemental resistances (that I will add don't often make any sense whatsoever, like why do bandits and bullywogs get fire resist?)
Here are my proposed solutions
Elemental Admixture metamagic feat: add 1 spell level to change the element to one of your choosing (maybe add to sorc at 10th level)
Greater Elemental admixture: same as above but adds 2 spell levels but includes Force, and negative and positive energy
A few specific suggestions
-add 2x damage on disintigrate
-remove 15d6 cap and add freeze/slowdown to cone of cold
-just take greater chromatic orb behind the chemical sheds and put it out of its misery
-remove damage cap from Freeze
-most spells need to have their damage and scaling increased significantly