No, they're not that good. More like T4, similar to a Warlock... until they hit level 20 and can spam gate. But even when you pump their skill up, their abilities really aren't that great. The possible exception is using their repair utterance to repair scroll tablets (which are an option in Complete Mage instead of scrolls, you get tiles that can be broken to get magic, and with the repair thing you could spam them).
JaronK
Some stuff the the Truenamer can do.
[spoiler]
Essence of lifespark allows you to hit someone with a
no save negative level. At level 14 you can do this as a swift and/or a standard action.
Caster Lens let's you shut down a casters highest level of spells without save (due to making them have insufficient CL to cast.) You can Do this as a swift action at level 10.
Confounding Resistance lets you give mettle and evasion. You can do this as a swift action at level 10.
Energy Negation let's you do 10d6 damage to a target, no save. With Strong op-fu, you can do this as a swift action at level 6. You will almost always be able to do it as a standard action. At 6th level, the warlock you compare this class to is done 3d6.
With
Inertia Surge, you can get a Freedom of movement effect at level 1.
Starting at level three you can use
Silent Caster to Save or suck casters.
When you remove the save on slow, it is an incredibly harsh de-buff. Available from 6th level, in the lovely form of
Greater Speed of the zephyr.
Hell, throwing around +5 or -5 on
all skill checks is easy for most classes at 1st level. It isn't at all special that a truenamer can with
Universal Aptitude.
Or a no save sanctuary effect. I bet that's incredibly common.
Ward of Peace is useless.
Plus, with how the class works, spend one utterance on any
word of nurturing, and you are the perfect out of combat bandaid box for free.
Able to make any suit of armor grant immunity to Sneak attacks and critical hits? Everyone has that by four level.
Fortify Armor is barely worth mention.
Also, the fact you're talking is the only thing that marks you as a psuedocaster. Nothing in the rules say you must speak loudly. As far as the enemy knows, reality is re-writing itself because it likes you better.
Hell, I wouldn't be surprised if a good truenamer could take down a tier one if the Truenamer had the element of surprise. It could easily take down a overconfident tier two. It can't kill someone abusing contact other plane, but it sould be able to put up a fight for anyone short of it.
[/spoiler]
Truenamer is a class that allows you to have the cheat codes for the universe. Pick the right codes, and you can really mess stuff up.
I'll admit the truenamer isn't tier 1. However, It get's lot's of things no other class does, many of these things are stuff
nobody will expect.
Use the uncertainty to you're advantage.