The game I would most rate a true "Space Opera" was an old board-game by SPI (Simulations Publications, Inc) called Freedom in the Galaxy.
It actually involved heroes, several of them, and the heroes could undertake missions during your turn, in a separate phase from the moving of fleets and armies. In addition there were political considerations, with each planet's politics rated on a sliding scale from imperial sympathy to rebel sympathy.
It even had a Rebel Secret Base
And Imperial Atrocities
To be honest, it was pretty campy. One of the imperial characters, supposedly an illegitimate niece of the emperor, was named "Thysa Kimbo". Another of the imperials was of a dog-headed race, and was named "Barca" (groan)