The fight against Braccus court of sceletons in the far east was much harder imo, the hardest in the game. But then I met them at level 5 and the lighthouse party at level 10. Guess why my experience is different than yours. For me the lighthouse fight was really a cakewalk...
Lord Crash, any fight can be too hard/too easy if you're too low/high a level for it.
Being three levels below the enemies will make for a tougher fight, and there's no fight in the beta which is challenging at level 10, because no enemy in the beta is above level 8.
Again me - as a fan of D&D and of the omnipresent mage as Stabbey might call me - I would vote for more deadly spells that have a low chance of succeeding. Not only for the player but especially for enemies. "Finger of death" or "entomb" are good examples from D&D. If they suceed one character has almost no chance to survive. Party members hit by deadly spells like "turn to stone" of "entomb" were even impossible to bring back by normal means or usual resurrect spells.
Are you suggesting that D:OS add some spells that if they succeed will screw a character unless there's a very specific recourse to curing them?
Okay, but on a scale of screwed from "just need a resurrect scroll", to "need a golden tongue from a winged basilisk which only appears by the light of the waning crescent", what do you think is the sweet spot?