I think they're trying to gain more mainstream appeal (if that's possible) and focusing on getting their sound out to more people. At first they used to put more work into their radio edits (Sexual, It's Not Right But It's OK), but then for the past two years they've literally been the club mixes with all of the non-vocal gaps taken out. Chris was very happy with the on-air success of No More Drama, so I'm guessing they're trying to recreate that. As for the club mix being so much less interesting, I don't know why they chose to do it that way. Maybe (hopefully) they'll follow up with a more energetic version, as they did last year with Don't Tell Me.