Hypothetically, the Devils should be a playoff team. Assuming the percentages normal out- as in they begin shooting at a normal rate and they get better goaltending (which over the last few games, they have been getting), they should be able to make it simply because they're a very good possession team. The trade deadline is a rather unique scenario for the Devils- they should hypothetically be buyers because they're going to be competing for a playoff spot. However, they have a lot of spare parts that they could move, so they could hypothetically be sellers. The question is what should they be looking for at the deadline?
The Devils could trade for a forward, namely a top 6 forward. However, it's completely unnecessary. Tom Gulliti mentioned that Dainius Zubrus was skating and could be back soon. With Zubrus back in the lineup, the Devils will get that top 6 forward that they're looking for. While he's not the best scorer in general, Zubrus is an effective top 6 player and should provide an upgrade over Steve Bernier or Alexei Ponikarovsky and more importantly, they're not giving up anything. Claiming Tom Kostopolous off waivers adds an effective bottom 6 forward who will push Krys Barch out of the lineup, while Steve Bernier can be effectively used as a 3rd liner.
As for any Dany Heatley trade, it's not going to happen simply because it would make very little sense. Heatley's way past his prime and despite his 6'4 220 lb frame, he's not a very physical player. Plus of course, Hockeyy Insiderr mentioned it so there's a 99.9% chance that the trade isn't happening.
The only potential trade I could see happening is one for a centre if Andrei Loktionov's injury is more severe than expected. However, I don't think it will happen just because even without Loktionov, they still have good depth down the middle.
Martin Brodeur will be in the lineup today, so there really is no reason for the Devils to trade for a goalie.
The defense is somewhat problematic, although it's probably not going to be improved by trade, but rather by just utilizing players differently. Of course, because i've mentioned it ad nauseum, i'm probably not going to say anything more than why would anyone fix something that works perfectly fine and instead turn it into a problem?
Being a Seller?
The Devils do have an excess of defensemen as of now. Ideally, moving one of them at the deadline would be the best, simply because it would net them picks (which could be flipped later for assets) or prospects. There are plenty of teams that could use an upgrade on their defense. Henrik Tallinder's contract situation (1 more season at around $3.4 Mil) makes him attractive for a team who could use short term help on their blueline. Anton Volchenkov might be harder to move because of his contract. Peter Harrold could be moved, but it's probably better to keep him around for depth- he hasn't been awful, but he's not the worst player.
Then there's Mark Fayne. While trading him might not be the best idea, the Devils could get the most out of a trade involving him. If there's a team looking for a young top pairing defenseman, they might be willing to part with some high draft picks or top prospects for him. It's not the most ideal move, but they'd get a lot more in return for Fayne than they would for Tallinder or Volchenkov. Plus with the Devils deep defensive pool, moving Fayne might not hurt seeing as someone like Eric Gelinas or possibly Jon Merrill could fill in Fayne's spot (assuming DeBoer wants to play defensemen instead of pylons).
The Devils have a few weeks to think about it, but while they could add some pieces, they shouldn't be too active at the deadline. If they can move a spare defenseman for assets, that would be ideal. However, there really isn't much to add to the team.