A few further issues raised now:
1. Player behaviour.
2. Trash Mobs vs "Normal Play"

Firstly, Player Behaviour. I've had great random parties, lastnight was my first experience with horror, trying to complete Castrum first time. I'd watched a vid of the run, told the party it was my first run. There was no communication, no marking targets and no strategy talked about. We beat it after a few deaths but it was hands down the worst experience to date. I'm actively looking for a FC on Sargatanas now so I can go with a few familiar faces.

Trash Mobs vs "Normal Play" - I think this highlights the core reasons people want to play games. For some unless there is a measurable reward then it is not fun, for others (i'm in this camp) the process of playing is the fun.

I ran a 2nd dungeon after Castrum. For all 4 of us it was our first, all communicated and it was an absolute blast! Only wiped once when figuring out what the big Tonberry was doing.