The Prime Directive has always been a bigoted form of noninterferrence solely based upon warp drive technology. Can you think of anything more ridiculous? Why would this even matter? Say a race has advanced genetics skills, the best medicine in the galaxy, the most advanced linguistic ability, the best architects found anywhere, the most wonderful musicians, etc. Nope, sorry...you're a backward species.
I don't *think* anything in canon has established that what makes a civilization worthy is necessarily warp drive - warp drive (or presumably any other fast interstellar transport system) is just a dead giveaway that the PD is moot for that civilization, because they are now out looking for other civilizations to interfere with them.
A few of the novels have said that there is a complex system of civilization analysis involved that gives a civ a score and determines if they are ready for contact or not, and interstellar drive is only one factor in calculating that score among others such as those you mentioned here. I like that concept.