Thusfar, Age of the Primes looks like another toyline that I'll skip
almost entirely, with exceptions being those that are either holdovers from
Legacy (more likely their 'Retro G1' remixes) or figures like this one,
which fits about as well into TransFormers as did the live action movie Dinobots or TLK Megatron.
I have to confess that my knowledge of the Primes is pretty much non-existent, both in terms of who they are and how/why they entered the lore... But, if I had to guess, it was probably Furman (and I'd be right). The idea of thirteen Primes representing aspects of Cybertronian physiology or society isn't inherently bad, per se, just... superfluous... And their introduction into TransFormers media really highlights how astonishingly easy it is for a moderately proficient writer to define authority figures and get a whole community of people to accept them as gods in a religion.
Nevertheless, we're currently at a point in the Age of the Primes line where there's only a couple more of The Thirteen to go - Quintus and Amalgamous, both of whom sound interesting in theory, but look terrible as toys - and I'm highly unlikely to add them to my collection... Let's see if Onyx Prime can help us ascertain why that is...