Disclaimer: I have worked with this author in the past and was so enamoured with the project that I've asked him to be considered as a future contributor for its growth.
When WotC first started talking about rules modularity for 5e during the playtest process, I was excited as an amatuer game designer at the possibility that modules could offer. The initial outing of modules didn't quite live up to boasts about the concept, but feats are a nice option. What Joshua provides is better. Reading it, there's an initial snap judgement you have to get over that the options he presents seem more powerful than the current crop of feats on offer. Individually that may be true, but the options for elves don't reinforce any one class above all others. Feats are powerful in concert with each other and your class features. The paragon race options simply reinforce the archetype of your race and include a few bits here and there to satisfy many classes without making the paragon options overly out of balance with what can be done by choosing the right feats: its obviously powerful, but not entirely game-breakingly so and certainly not more powerful than combinations that could be made out of the right feats.
It is absolutely on my list of must-have products from DMs Guild.