1) If (and this is a big if at this point considering how awesome Nina Dobrev has shown herself at playing Katherine, but it could also be too much work for the long run) they decide to permanently kill Katherine off at season's end, I was thinking of a way it might happen. Originally, I thought it would be Damon taking her out to save Elena's life. However, even as that thought was percolating, it occurred to me that it would be wonderfully full circle if Damon took Katherine out to save Jeremy! It would create a fantastic contrast to the premiere (you know when he snapped Jeremy's neck), but also helps to explain the bonding it looks like we're in store for between Damon and Jeremy. It also gives that much more credence to why Elena would look upon Damon as a viable romantic option (which she so does not now at all ... and frankly so should not). Well, one of the many things that need to happen to truly position Damon in any romantic viable way.
2) I'm pretty much convinced (although, of course, anything could change, I know, and I could be totally wrong) that Damon and Elena are endgame at this point, and also, that we are seeing the beginning of the end for Stefan and Elena. So ... I'm wondering if the show is going to try and begin to ease a potential triangle out of Stefan/Caroline/Matt and that way they'd have the Damon/Elena pairing to focus on alongside the Stefan/Caroline/Matt triangle. It seems that they are trying to really make Caroline the real deal for Matt as opposed to a placeholder until he can have Elena again (not from the show's perspective, but Matt's). Yet, at the same time, that Stefan/Caroline scene from episode two ("Brand New World") was filmed very intimately with close-ups, emotional bonding, tenderness, embraces, etc. And this show doesn't do things without laying groundwork for future episodes/character interaction, etc.
Now, if this is the plan, and it does take off and work, it allows Paul Wesley, Ian Somerhalder and Dobrev less strenuous schedules now and then. (Based on comments here and there, it's pretty obvious those three are working ridiculously heavy loads -- like 12-16 hours 5-6 days a week). So if we have the focus move to the Stefan/Caroline/Matt triangle, and the Damon/Elena pairing -- while, of course, still keeping the Damon/Stefan dynamic, and what surely would follow, Stefan/Elena tension -- the show can focus on the triangle in some episodes, giving Nina and Ian a bit of a break, and vice versa, giving Paul a bit of break. And, on top of that, they've got the Tyler/Lockwood werewolf story, as well as Bonnie, the witch.
3) Finally, I think the point of the Stefan/Jeremy scene at the top of episode two and the Damon/Jeremy at the end was showing the different kind of relationships that Jeremy is developing with Stefan and Damon. And that could come into play with Elena down the road. Remember Elena's sharp "Stefan!" in the premiere with how he was treating Jeremy? I still think that was deliberate. I wonder if it will come down to Elena turning to Damon with regards to Jeremy because, unlike Stefan, Jeremy and Damon are truly bonding whereas Stefan and Jeremy just have that casual, 'you're dating my sister' relationship. Elena would imagine that Stefan would care more for bonding with the important people in her life, but it's not happening.
Also, will the Damon/Jeremy bonding cause a different kind of friction between Elena and Stefan because I could easily see Stefan becoming jealous of that relationship. The last couple of episodes of season one and, especially this season so far, have shown that Damon is Stefan's first priority. He loves his brother, and it almost seems as if he's using Katherine's presence as an excuse to forgive Damon all of his bad behavior so that he can once more adore his big brother. And if Jeremy begins to develop that kind of younger brother relationship with Damon, I could see that giving Stefan pause.
I dunno, we'll see.