Borderlands is one of those games that gets you so sucked into the world that it's hard to find something that fills the void once it's over. I guess that's why they have playthroughs 2 and 2.5 :P

The first game felt like they made the most of what really boiled down to simplistic gameplay (very little by way of skill customisation and so on), so I'll be interested to see if the sequel is as effective if it brings in more features. Whereas there are great games like, say, Mass Effect where there was a lot to be improved upon in the sequel, to me there's not a whole lot in Borderlands that I would change.