I think the trolls have the nastiest combo in the game. FIrst they blind you, effectively halving your skill points AND you can not use potions or heals, their hits causes disease which further lowers skill and on top of that they like to go berzerk.
I've had overpowered heroes for that area walk into a troll and a bit of bad luck enables the troll to score a few hits without retaliation. It cribles my skill and I can hardly hit the beast because it dodges, I can't run away, I can't heal, and every round it slashes a few gut points off of me.
With that said. Monster drops are not dependent on level (or age) you are just into a streak of bad luck. I will repeat my advice from before. If you encounter something which doesn't drop anything worth your while then run.
The dock is accesible from the courtyard but I think there is a level requirement. Perhaps 24? I can not remember.
In general you shouldn't bother with the goblin mounds. Instead hang around the dunjeons. The drop is better, and there are fewer gear eating worms and swindlers.
The vortex is placed at the goblin mounds, but is a dead end that is left for a future expansion of the game... (We've waited years, so don't be too optimistic.) A character "Evil Fred" guards the vortex and he is mean and knows all the tricks so don't go there unless you want to prove yourself.