On one hand, it's sad that spells like Fireball become useless as levels increase. On the other hand, before, high end damage spells were largely useless next to fireball before. That's also pretty sad. The evoker in my 2nd ed game maxed out his number of fireballs (using spell points) because the high level attacks cost more for little to no extra benefit. And then he used some Mnemonic Enhancers in 4th level spells to get even more fireballs. Metamagic provides some options for extending the lifespan of spells.
Saving throws (especially wrt save or die/incapacitation effects) are rather problematic. Even characters with strong saves can be taken out if they roll poorly. Thus, even a low indvidual failure chance skyrockets in total when a character is under sustained magical assault from multiple casters. In one ambush, almost the entire party was taken out in round 1 by a volley of 2 confusions and 2 greater commands. Thus, there's a pressure to push saves as high as they'll go; high level characters often load with with pale green ioun stones, luckstones, and other misc bonus effects since cloaks of resistance aren't enough. If you save 75% of the time against a high level effect, that means your high level character can drop instantly 1/4 quarter of the time. And if the character is hit with 2 such effects, then he only has a ~56% chance of coming through unscathed. That high save doesn't sound so good now, does it?
On the other hand, the pressure to boost saves to handle intensive barrages or tricked out monsters can make casters nearly useless with any given action. A baddy made to live a couple rounds vs a few casters dropping save or die effects on him will have saves so high that spell attacks seem futile. The character above seems fragile in that there's a decent chance he'll die in the encounter, but think of the caster's PoV. He's got a 75% chance to suck each round, AND be out a high level slot. It's frustrating either way.
Stoneskin was nasty in 2nd ed vs giants. I remember the party screwing up in one battle against fire giants, and the 2 wizards were surrounded by like 10 giants as a result. Of course, everything bounced off and the party won.