The "conventional wisdom" seems to be that prosecutions for torture are unlikely, but I think the CW is misplaced.
First of all, there's no statute of limitations for war crimes, so it's presumptuous to assume that the political situation 10 or 20 years from now won't allow for it. Just ask Pinochet.
Speaking of Pinochet, there's also the fact that war crimes are universal jurisdiction crimes, so there's always the possibility of the prosecution in a foreign court. Still, here I am talking about US prosecutions.
Despite his talk about "moving on" and "looking forward: I don't think there's any indication that Obama has ruled out prosecutions down the road. He's a skilled politician, though, and I think he recognizes that he can (indeed must) let the case build for prosecutions over time. He has some very pressing issues that must be dealt with NOW and getting bogged down in legal action that will unavoidably take years to resolve is, frankly, stupid. Better to let the pressure build slowly.
Factors that will build the pressure will include finding out more about what, exactly, was done. Shining a bright light on the prior practices and who authorized them will help build pressure to act. As a matter of fact, under the relevant treaties and laws the government will HAVE to act eventually, and at least open investigations. Given what we already know, investigations seem likely to lead to charges and charges will necessarily lead to trials. Whether they lead to convictions is hard to say, but people have been convicted for less.
What Obama had to do now on the torture and related executive abuses is ensure that they STOP immediately and that there be a complete repudiation of the Bush approach. His executive orders and appointments both achieve that aim. There has been some quibbling from the ACLU and some outer human rights advocates that Obama left him some "wriggle room" here and there. It's their job to raise these kinds of flags, but I put little stock in them. Keeping some third way of dealing with Gitmo detainees besides the regular courts and UCMJ available is simple political prudence. Despite the appalling incompetence of the Bush people, it's probably that at least some of the remaining detainees at Gitmo are actual, bona fide dangerous terrorists that can't be released safely. Unfortunately, because of Bush policies, they probably can't be prosecuted now because of torture and abuse. So some process that keeps them detained will have to be found.
Obama has clearly laid out that openness, rule of law and humane treatment are the default values whenever in doubt. This is the opposite approach from Bush, of course, but what it means is that as it percolates down the chain to the lowest levels that things will change in a concrete way. Just as Rumsfeld's decisions led directly to Lynndie England's actions, so will Obama's lead to changes It all starts at the top.