I wanted to make a character that's kind of the classic cardslinger archetype (think Gambit, Twisted Fate, Luxord, etc). My original idea was to just make an Arcane Trickster Rogue that uses reflavored Darts as their main weapon, but it turns out they're not all that great and I don't feel like taking half a dozen feats/multiclass options to make it halfway viable, so I was wanting to simply homebrew a new Playing Card weapon that I could give them instead. The problem is that I've never homebrewed anything before and, while I know that throwing weapons aren't that great, I'm still new enough to the game and it's mechanics to pinpoint what their most glaring issues are and how to fix them.

Therefore, my question is this: What do you think are the biggest problems with throwing weapons, and how would you go about fixing them?