It depends on your style and tolerances. If you are very methodical and do everything the first time around, then the replay value would be less. I re-started the game a little while after completing it (the only time I have done so for an RPG without more than a year going by), though did not finish it again. Some people have completed it multiple times, or even dozens of times.
Personally, if there are only simplistic quests and little plot (D2, what I played of the Sacred demo), then randomly generated areas are not going to make it any more replayable.
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