This may or may not help or might even add more to the confusion. but here are some general observations that I have made with the assumption that you have a team that can address some of the more specific/niche tasks (DB work, application server configuration/support, infrastructure integration troubleshooting.)
A Pega developer should have the following:
- the minimal two courses (SAE, SSA). (Certifications will help -- mostly from the studying -- but increases your marketability)
- a design / thought process first. (I have seen developers that want to start coding/hacking first get into trouble through poor design of solution)
- enterprise mindset. (every time you create a rule within Pega, is there someone else on the team / in the organization that could benefit from this work)
- access to a more senior resource to help guide them
- be willing to try different things and learn from mistakes/errors; Pega development can sometimes challenge a developers experience/knowledge and the willingness to flip this thought process will help
- approach the task at hand incrementally (provide feedback to oneself plus business users)
- able to interact with business users to communicate direction (highlighting problems with going away from OOTB)
- know the designer studio (explorer section, clipboard, LIVE UI, tracer, search) VERY WELL as these are extremely key to troubleshooting/verifying what Pega is doing (if it's not doing what you want it to do). In most cases, Pega is not doing what you want it to do, is because you haven't told it right.. :)
- if OOTB Pega can't solve it through a vast list of industry-standard approaches, a developer can revert to Java to meet the needs. [not all Pega developers on a team need this, just one or two]
- Custom input field validations (aka international phone mask) if not available already (there is a large list here) can be with Java snippet code. [not all Pega developers on a team need this, just one or two]
- in the beginning, the more hands-on with Pega you can be the better, as it results in an increased comfort level and improves the knowledge gain.
There is probably a lot more and deeper detail that I or others could add but does this give you a good start?