What features of the lore of Theros did you prefer over Dragonlords?
I also have both. I'm not sure if I prefer the setting of Thylea (the setting for Dragonlords) to the setting of Theros, they are both very similar fantasy versions of mythic Greece.
The main difference is the titular "dragonlords" which are hard to discuss without spoilers. The dragonlords are mythic heroes who, well, rode dragons and saved the people of Thylea from the oppressive titans. During the course of the adventure, the PCs have the opportunity to become the new dragonlords of Thylea, and even possibly new gods. While the adventure has it's rough spots, overall it's pretty damn epic and seems like it would be a lot of fun to run.
The two settings draw from the same well and have very similar themes and tropes. The old gods, or titans, are oppressive, violent, and bad news. The new gods (Olympian equivalents) might have saved the world from the titans, but are petty, selfish, and vindictive. The gods play a major role in both settings, but there is more connection between PCs and gods in Theros with the piety system.
I'm thinking about running a Greek-inspired campaign blending Dragonlords and Theros, and possibly some of the other recent 5E "Ancient" settings Morrus mentioned above. Haven't put a lot of thought into it yet, but I think the biggest challenge is decided which similar option to go with in a few cases.
Dragonlords definitely has more robust character options, and they are available for free in the
Odyssey of the Dragonlords Player's Guide on
DriveThruRPG.com.