It's set up for either four-time champion O'Sullivan to retain after not playing all season or Selby to win the Grand Slam of the Worlds, Masters and UK Championships.
Aside from those two? 2005 Champ Shaun Murphy is a good player and is always a contender for titles, while Ali Carter is more than good enough, and arguably should have won at least one by now. His problem though? His next match is against Ronnie O'Sullivan, who he has NEVER beaten in World Championships (including a couple of finals)
Poomjaeng is a bit of a sideshow. he might get a good run to the QF, but he fluked a fair few shots against Maguire. He's good fun though, but I wouldn't want him as World champion.
Ding Junhui is as good a shout as any. When he plays, he's a fucking dynamo, and very few can match him. e seems to have settled this season and could finally have a good run at the world championship.
Judd Trump should be good enough, but he always seems to either lose focus or throw away easy chances or something like that in recent big tournaments. Still, not to be discounted.
That said, with the amount of top players who've gone home early, I can see this being a year when a lower-ranked player shocks everyone (ala Shaun Murphy). Robert Milkins, with some of his play against Neil Robertson, has to be in with a shout if he can carry on playing like that.
Snooker is an acquired taste, and is only popular in certain parts of the world (mostly Asia and the UK). In fact, I can't name a single US player off the top my head.