I share those sentiments towards William but honestly, we cannot be surprised. I am not a psychologist but looking at what he went through during his childhood and growing up it makes perfectly sense that he is not anywhere near a commitment yet - at least towards Kate. Instead he committed himself to the RAF - a perfect opportunity to escape the pressure of moving on with Kate what is obviously not on his agenda. I can't imagine a more powerful gesture towards the public than that, saying: "Forget about me getting married in the next 7 years!" And rightly so - William has all the time in the world, he can still get married 10, 15 years from now and depending on how he decides to fill that timeslot (focussing on duty) nobody will even raise an eyebrow. But it leaves Kate standing out in the rain.
There have been enough "proofs" now that Kate obviously is not the one special person - in sugary terms "the love of his life" - otherwise he would be much more protective of her. It would be an easy thing to do but, no. I believe they do have an agreed position - William simply told her that he is not ready to commit and doesn't know when that will be and Kate accepts this position, maybe because she loves him and because she doesn't have a choice, it's like "sink or swim". I am dead sure if she enforced a decision she would get her leaving ticket, she knows that and therefore keeps quiet. William is determined not to make his father's mistakes, maybe he already had a glimpse on "true love" during previous relationships (Jecca?) without the option of a serious relationship. Maybe this is what he is missing in his serious but handy, comfortable and standstill relationship with Kate, knowing at the same time that it might not be enough for a life together. Kate could easily break under the pressure as his wife and William would find himself in the same position as Charles, failed having pursued "true love". William won't go for second best when chosing a wife, that's for sure, he can't afford to do so. Unfortunately for Kate, she doesn't have another 10-15 years, and the longer the non-decision-situation goes on the more she is being labelled "second class". This whole relationship has turned into a win-win situation for William but into a lose-lose situation for Kate.