I believe Andy wants to avoid any expectation (or the opposite) going into AO so he opted out of Brisbane/Doha. A few practice matches is probably enough. He used to do that prior to his Slam wins. He wants to make sure by the end of this year that he's ranked within top 8 - that's why he's playing back to back tournaments. WTF feels more like a smokescreen.
Anyway, 2015 is definitely a key year for Andy. If he doesn't do well then he may as well be done and will probably remain as a top 10 or 20 player at best, but I think he'll be keen on proving his naysayers wrong and will probably storm back to top 4 - where he left things off. AO would be a great indication of things. This year, especially right now, he's spending time and putting in extra effort to build the momentum. And I am sure he's building it for a good reason.
His 2nd serve is his weakest link, there's no doubt about that. Even today, I think he won about 6 points out of 20 (30%) and that's pretty poor. Melzer himself played pretty poor so it doesn't look too bad on Andy but against others, it is the deciding factor for his win or loss. His 1st serve has been pretty consistent since Shenzen so that's something he doesn't need to worry about too much right now. I have no idea what Mauresmo (and Andy) has in plan for the 2nd serve. I am sure something could be done about it.
As to others, Wawrinka will probably collapse early due to expectation and perhaps same goes for Cilic but I will bank on Cilic more at this point. I don't think he got completely carried away by his US Open win. Raonic will be lethal or so I get the feeling. Whoever draws him will be a handful. He's something of a worry for us Andy fans. You didn't mention either Dimitrov or Nishikori - Nishikori in particular I believe will be the most dangerous. He'll be my 3rd favourite after Andy and Nole.
Yes, it will be interesting to see how things pan out for Thiem (I like him very much), Goffin and Kyrgios - Especially Kyrgios given the venue. I feel 2015 will be more interesting than 2014.