Missed opportunities.
So are the truenamer and shadow caster like Bruno? We don't talk about them?
The truenamer had a host of mechanical problems that made it not work well; notably, using truenamer abilities required a skill check, but the DC increased at a faster rate than the skill bonus did, so by default it became
harder to do anything as you advanced. What's more, the DCs would increase rapidly if you attempted to reuse the same utterance during the same day, and the rewards for successfully performing an utterance were generally unimpressive—and the targets sometimes got saves too. For instance, at level 8 you could learn
Fog From the Void... which was just the
fog cloud spell, available to most casters at level 3. Except it wasn't the same as
fog cloud, because in 3.5 that spell would last for 10 minutes/level, with a range of 100 ft plus 10 ft/level, while the truenamer version lasted only 1 minute and had a fixed 100 foot range.
If I remember correctly the rules were also incomplete. All that stuff I mentioned about skill checks? The rules just said that the DC for performing an utterance is 15 + (the target's CR x 2). But
Fog From the Void doesn't have any targets, and the rules don't say how to set the DC in that case.
Shadowcaster was better; it's playable, at least, and moderately effective. They're a bit underwhelming and the least flavorful of the classes in
Tome of Magic. I found them to effectively be spellcasters working off a very limited list, but they weren't bad per se.