A valid point. I find myself yawning a bit at some points but I think that is because I've just started each character to level 10 to get a 'taste' of them. The endless groups of monsters gets a bit repetitive but DD was like what in a few places also. After reading the sacred forums there are a lot of ways to build characters so I belive a lot of 'experimentation' is in order.
Like Diablo 2, the item-hunting is a lot of fun. DD had a lot of 'fixed' items, knowing what you will get after a certain quest/battle has its advantages and disadvantages.
What DD has is more interesting quests and a unique approach to character building. Any skills can be chosen.
Sacred has basically set character stats but messing around with all the skills can give different results. Its interesting, I'm just learning to specialise with each character now.
Both games have a massive world to explore. This is a lot better than Diablo 2.

No specific opinion here as I like both games. I just tried to point out some aspects of each game. I guess I included D2 as well because you can't really avoid it. It was one of the genre-defining games after all.

" Road rage, air rage. Why should I be forced to divide my rage into seperate categories? To me, it's just one big, all-around, everyday rage. I don't have time for distinctions. I'm too busy screaming at people. " -George Carlin