Illusory pit should be banned (it should also be disabled completely but that's for another topic).
I'd be happy to provide logs where, more than not, orb spells miss completely and just give a free round to the opponent, so I can't bring myself to agree that there's anything wrong with them. There's a working mechanical way to avoid them, multiple spells of similar and lower level that can completely nullify them without even worrying about having to avoid, and they're no less difficult to dodge than harm or the other priestly touch spells. As my logs show, some PCs are very
good at handling them. That a castter's player just happens to know what spells best harm what classes and builds is a product of quite a lot of trial and error over months and years, no bug. Areia prepared a ton of fortitude-save spells to win her first wizard bout and would do likewise in fighting thieves, while orb spells she completely eschewed because those classes happen to be good at dodging touch spells. I'm not sure anyone would suggest she avoid fortitude spells to fight wizards in the future, though. One of my fighters is positively horrible at avoiding touch spells, another is excellent at it. It's called balance between builds. Some PC make-ups are better at some things while being worse at others and vice versa.
As for disintegrate, yeah, it just does damage, enough to bring a wizard down to DYING in one shot if it hits, but just damage. There are myriad ways to avoid, resist, and recover from it, too. I like to think these sorts of events are excellent ways to see what works and what doesn't with your PC's strategies, but that's just me. It's been lots of fun so far.
Nascentes morimur, finisque ab origine pendet.