Question is right there in the title. I'm a bit unsure of the relative "worth", so to speak, of things like trapfinding, trap sense, poison use, no trace, uncanny dodge, etc. Rogue Talents and Ninja Tricks I get, they're feat-equivalent, but the others I have a harder time getting a fix on. Should I be diminishing sneak attack to compensate for particularly powerful abilities?
For the vast majority of Arcane Trickster builds, there's no reason you'd ever want to take more than 1 level of Rogue or Ninja. Even a single additional level of spellcasting advancement vastly outweighs what you get from other classes. The typical entry into Arcane Trickster involves 1 level of Unchained Rogue, 3-4 levels of Wizard, and the Accomplished Sneak Attacker feat. Since the prestige class focuses so heavily on casting (1/2 BAB and full spellcasting progression) doing anything other than maximizing your spellcasting ability works against the strengths of the prestige class.
I'm sorry? I was talking about making my own archetypes, not... whatever it is you're talking about.
In the context of Rogues, "AT" is a shorthand for Arcane Trickster, hence why I thought you were asking about the prestige class. Anyways, I understand what you're asking now so hopefully I can give a more useful answer.
First of all, I would say you can't put a hard value on many class features. It's always going to vary based on the needs of your build and context. Moreover, I would personally argue that a good class or archetype should offer you abilities you can't replicate by other means. Class features should, to a degree, be special.
* Trapfinding has an equivalent trait called trap finder. Traits are ostensibly worth half a feat, however campaign traits (this is a campaign trait) are often significantly better than regular traits. As a result, I'd take that valuation with a grain of salt and treat it as being a bit more valuable.
* Evasion is incredibly valuable, and one of the best defensive abilities in the game. This definitely falls into the "it's special" category. An archetype that trades this out should give something distinctive and meaningfully unique in return. For instance, ninjas get their ki pool and the unique abilities that go with it instead of evasion.
* Due to the existence of the Accomplished Sneak Attacker feat, each sneak attack die is valued at 1 feat. I think this is a tad overpriced, but it's close enough.
* Poison Use is often considered useless. Poison in Pathfinder is a bit underpowered, but what really kills it is being overpriced. Even if you have this ability, it's still not worth using because of the cost. As a result, many people are of the opinion that trading out poison use is always an upgrade.
* (Improved) Uncanny Dodge has a lot of miscellaneous benefits. It's not as good as evasion, but it's a pretty nice suite of benefits. Again it skirts the boundaries of being special due to there not being a good way of getting these benefits elsewhere. It's just not as good as evasion.
With regards to ninja tricks and rogue talents, I'd also mention that the talent at 2nd level is significantly more valuable than the ones gained at later levels. This is because it qualifies you for the "extra talent/trick" feat. Many builds can simply use feats to make up for missing talents, but losing the 2nd level talent delays how earlier they can can qualify for such feats and can have a huge impact on such builds. As a result, you should ensure the 2nd level talent is only traded out on archetypes that give a very powerful low-level benefit to compensate for the fact that it will otherwise cripple many builds at low levels.
I'm sorry? I was talking about making my own archetypes, not... whatever it is you're talking about.
So are you trying to shorten archetypes to ATS? I have to admit the lone reason for looking in on this thread was to try and figure out what you meant by ATS as I've NEVER seen that.
Thank you for the advice, Dasrak~ I will take it to heart.
It's weird that y'all have never seen that abbreviation... Maybe it's just a thing with the group I'm in. *shrugs*