I loved the first one and was pretty disappointed with the second one. D2 improved a fair amount of the gameplay but there was no story to hold everything together, so the whole game felt like one tedious sidequest after another, even when you were playing the main story quests.
I feel the second one had too much stuff and spread itself too thin. The first was very tight and solid and thus felt like a complete experience. Darksiders 2 has everything and the kitchen sink and, while I'm impressed they actually made a game that worked, felt a bit loose because of it.
I do think the platforming/traversal in 2 is leagues above 1, though. But I still prefer 1.