Thematically, the warlock is one of my favorite classes in 5th Edition Dungeons & Dragons. But mechanically, I felt they were underwhelming. My character felt really cool in my head, less so in an encounter. I made a tweet about it and it turns out I wasn't the only one who felt this way. I teamed up with @polyamorous_q and my For Science Crew DM @Persnicketese and we took a crack at updating the warlock class to play as versatile and deep as it thematically feels.
Most of our work focused on the Pact Boons and the Invocations, with some flexibility added to Mystic Arcana as well. Take a look, try it out if you can, and let us know how it plays and if it needs any adjustment.