Hello!
I'm asking myself why there are only up to 3 slots for heroes? I would really like at least 6 slots to log a multiplayergame correctly

Been like that since day one, pretty much turning it useless for non-soloers.

Just put each players heroes in as a seperate entry.

Yeah, it's made so that each player enters their results separately. This has some cool side-benefits of being able to then do the 'compare quests with a friend' under 'Quest View' to see and compare Sphere Weights and Hero Percentages within your group.

What we do, is I use the score sheet printouts while our group is playing, keeping track of scores and everyone's heroes, and then once they leave I enter my results in the quest log and email the information to my friends for them to do the same.

It's worked pretty good for us so far.