Well, we were an Asmoah Gyan extra time goal from doing this in 2010 (I believe we win in a PK shootout), and most (all?) of the key players are back, so it doesn't seem far fetched.
If we get a decent draw quarters are possible but my feeling is that the field in group stages and knockouts is going to be much stronger in 2014.
2014 was notable for France and Italy stinking it up but I expect both of those to sides be in the knockouts in 2014 as well as an overall stronger cast of teams from Europe in general when you throw in, say, Belgium, instead of Slovenia etc.
In South America, there will probably be a bit more upper tier quality as well with Columbia added.
I'm not saying that we couldn't get out of group and win a match but I could also easily see a much tougher group and/or knockout draw where we'd be much clearer underdogs than in 2010.