It's also true that one person's "nightmare trip" is another person's "no problem." People go in with different expectations, *** different things trigger disappointment in all of us.
But regardless of why someone is upset, if it truly matters to them, then they do need to let Disney know.
For those upthread who did not get the responses they desired, it can be helpful to let Disney know that you expect a call back, or a detailed response, or compensation or ... whatever. Lots of people sign off with, "I wanted you to know that this happened. Thank you!" *** never ask for a response. Disney's daily volume of mail makes it impossible for them to reply to everyone, so specifically ASKING for a response will definitely up your chances of getting one.
***, as someone also mentioned upthread, the absolute best time to address any issues is while you're at Disney. If the ten-day trip was truly a ten-day nightmare, I'm hoping that the OP didn't wait until returning to address everything. Details fade, emotion takes over, *** something that could have been dealt with quickly, easily *** to the Guest's satisfaction if done immediately can take on a life of its own when addressed weeks later. Not to mention that, upon return home, things that didn't bother you at all at the time tend to get pulled into the "post-trip vent", *** Disney starts getting blamed for all sorts of stuff that didn't really go wrong.