So, in some ways I 'm lucky having only 1 player, because... less people to agree with! But I guess we are both compleatists , our selves, since we want to own and play it all. By the way we are 58 and 56 years old.
We only play about once a month on average, though if don't play in a month, we may double down and play longer/more on an occasion.
Because Dragons is *not* perfect, we do some house rules which I've mentioned many times; mostly to delay the scales - to get more of other things going on in the game.
I do find that the flavor of Dragons is intense and doesn't seem to go well if an alt ending seems contrary; ie; after foraging through the Dragon Realm/Inner region, you finally reach the CoC and find... the Demon Lord... or the Eagle Kind, or...
But we mostly don't mind, because in our two player games it is not unusual for us to call it because one of us just dies completely before either of us reach the Crown.
It is more about the tapestry or "story" of the particular game, rather than the competition. I think we're not as goal oriented in the playing, as most players may be.
Someone else indicated that the immense Adventure deck, of all expansions, limits a player's ability to encounter every card. Some cards may never be encountered if one uses the entire Adventure deck from all sets.
I guess I think that is a concern, but I would think that the more players in a single game means more cards will be ultimately played, encountered. In our 2 player games I don't feel that we lack the potential experience. One doesn't get to encounter every possible happening in real life either.
Decks that are tailored for a game, or to exclude cards / themes can also mean that the flavor of the game may be too specific. The world is very Icy. Or the world is very Haunted.
So for me, I like the world to have a bit of everything.