In regards to end of the world type main quests... seriously.. With Oblivion gates, we're talking about a demonic invasion from hell... gates from which armies can potentially march out of... A few dragons here and there is really nothing a few well trained archers cant deal with. Having the Oblivion crisis as a mere precurse to the dragon attacks seems a little anti-climatic...

True enough that Oblivion gates were much worse. Demons form hell basically could pour out anywhere. Dragons had been slain by the blades oblivion gates win.

But gameplay wise id rather fight a million dragons than go back into one more damned oblivion gate. It got repetitive as hell, but dragons are too, and I avoided them at every turn.