Let's try this. Rank the Truenamer in these situations.
Bare: Using nothing but Core and ToM. No magic items.
This really means your being screwed over, can't even get items that you make yourself. I imagine the artificer is pissed.
At 20th you could have 23 ranks, 3 skill focus, 9 from intelligence and 2 from master work item, That gives you a 37 skill check. you have -8 to con from being an elf and really old, you can heal 54x5x3 hp to the party and 54x5 to your self, a third of this if you feel you can't spare 5 points of con. Gate can be done on a 8 the first time, solid fog and control winds on a 3, transmute rock to muds-2, shockwave is at -7. Do to the utter lack of magic items Lexicon of the crafted tool is useful, you might even want to pick up quicken with it as they are Dc 25 so 45 with quicken. Can disarm with Seize item, heat metal, or transmute a weapon when fighting golems. You easily have 6 uses of each of these.
At 15 the skill will be 6 points lower, and the DC will be 10 points lower, which means it needs to roll a 14 or better to affect equal CR creatures, shock wave at -1, crafted tools can each be done 3 times before needing to roll, unless the opponents have magic items.
At level 10 it should be 13 ranks, 3 skill focus 7 from intelligence and 2 from masterwork item. So 25 versus Dcs of 35, your in the coin flip area, you likely picked up shockwave which you can do on a 5 the first time around, so not too bad I guess. Can go for a +5 buff at 60% chance from universal aptitude.
Can heal about 500hp to the party and a 100 to yourself, which is actually more than you can heal at the higher level if you didn't want -8 to con.
Which makes you on par with a healer at healing out of combat.
So I guess over all I would say tier 5 as long as your a middle age gray elf. The lexicon of the crafted tool and the Perfected Map are what the class is riding on at later levels. As the Evolving mind starts to devolve those start to pick up the slack. Also if the encounter is multiple creatures it can start to affect crap, a battle with 4 CR 16s at level 20 means that the TN needs to roll a 10 to affect them. Or 4 CR 6s at level 10, 2s all the way.
Skill-boosted: Using skill-boosting shenanigans, but no magic items yet.
The artificer still hates you, Add 4 to the above checks from illiterate, and a feat from OA and 3 from power sigil, or 3 from that one eberron elf. Then if elder evils is done add another 7 at level 5 every other round.
Going for other classes a level of exemplar and marshall will leave you with another 8, which gets you 60% shot at level 20, at 15 80%, and at 11 you will have a 100% odds. 85 at 10, 90 at 9, and 95 at 8 and 7. can also take a feat for lucky dice for another 5% when it gets a slot open.
Magically-enhanced: Core and ToM, but with magic items.
Yeah, I finally get the item that I am willing to make my self, add 5 at level 5, in the first section, and 12 to level 10, from the +10 item, and a +4 headband after that, at 15 it should be a +6 item if INT, and a +10 item of TS and a luckstone, so success on 1s. Also pays for PAOed for another +10.
Screw this: Skill-boosting shenanigans plus all the magic items you can get your grubby mittens on.
Add another 4 to the last tier, then item familiar for autoquicken.
That should give us a more accurate reply than the discussion we currently have going on - though not as accurate as can be.
I kind of think that an outline of what the TS number is going to be will be more accurate, considering that with core and magical enhancement it will wind up making the checks on a 1, and there are many ways to get to that score.
I'll likely add more later
