How Come?

In Presearing Ascalon I need another player to open the gate to the Northern Lands in order to complete a quest. I also need another player in order to acquire a resurrection signet. As far as I know there are no more quests in Prophecies that require another player to complete it. Why is this? Why are these two quests the only ones that require another player?

It's an introduction to group play, which you may want to try out some time.

Also, remember that Prophecies was the first campaign of the trilogy and it has a different approach to things when compared to Factions and Nightfall. In many ways, Prophecies was a prototype for things to come.

All in all, I think Prophecies is overall one of the most challenging chapters when played through. The degree of difficulty scales well with character level pacing, profession skills and improved armor acquisition. And, the progress is epic in scope.

Also, remember that in Prophecies, there were no other characters coming over from other campaigns, so the design was focused on first time players and Prophecies grown characters.