It's been a while since I've updated this guide (3 months!), mostly because I've been working on the Wilderness Survival Guide.
In this new version I've changed a bit the dragons, allowing players to customize them instead of using one base template for them, inspired by the ranger beast companion subclass, but since I wanted everyone to have a dragon, I decided to keep it as a Prestige Class.
Reddit link: Dragon Rider Prestige Class (2nd version) - Customize your dragon!
I'm open to suggestions, comments, and ideas for improving this prestige class and balance it as much as possible.
On a side note, I'm thinking on expanding this prestige class to a more generic beast rider class (like riding a phoenix, an elemental-like horse, a hypogriff, a bullette, etc)