If you’re looking to hire a competent UX professional, do not ask for “Experience with Adobe Tools” in your job description. Especially don’t ask for PhotoShop. Even visual designers are waking up to the fact that PhotoShop is not a good software UI design tool.
UX design is a distinct skill set from visual/graphic design. They are complementary, and some UX designers are competent visual designers while some visual designers are competent UX designers, but they are still distinct skills, much like development is distinct from design.
A UX designer should basically never use Photoshop. Illustrator is a decent hackable tool, but if you’re going to go that route, you might as well just use OmniGraffle. Still, all of these are basically just for static wireframing/UI comps, with varying levels of hackability to communicate interaction design intent. Adobe had an interesting UX design tool for a while–called “Flash Catalyst,” but they killed it, because they killed Flash (I deduce).
If you’re going to pick a software tool for interaction design, it should be one that is suited to exploring interactions, which implies interactivity, i.e., as a designer, I can say, “when a user does <insert name of user action here>, the app should do this…” At a super bare minimum, clicking should be supported, but seriously, what viable apps these days only support static, full-page/screen refresh navigation?? So then you get into needing to explore and express transitions and animations. I’m not talking about fancy dingbat silly animations. No, I’m talking about animations that help users understand and interact effectively with a given UI design.
At this point, the software tools that your average competent UX designer can grapple with get reduced. You can of course code prototypes, but that’s generally not the best idea. So you want a tool that allows a UX designer to explore and express user interactions and app responses to those interactions but doesn’t get them bogged down in code.
Now I am biased having worked extensively on it, but the only tool that really qualifies there is Indigo Studio. Sure, Axure is another alternative, but it is significantly more complex to use and tied to the details of the Web platform.
So if you’re going to ask for a software tool competency for a UX designer, pick one of these. But really, as long as a UX designer can effectively explore and communicate design ideas, it doesn’t matter what tool they use. If you are constraining them to specific tools, something is wrong with your process. What you need to look for is evidence of good designs–both designs and implementations, as well as evidence of design research and evidence of design evaluation. Ask about their process and techniques they use to discover the best designs. Just don’t ask for Adobe tool competency.