I suspect they avoid going into too much detail because they know it would expose any poor decisions and cause potential uproar.

For example, they nerfed Expedient on SCH because it was "too strong", but didn't go into the exact situations it was overpowered, why it deserved a nerf more than something like Macrocosmos on p3 and the thought process behind the decision. Changes are if they did, it would be some nonsense like "it let us finish dungeons faster than intended" or whatever excuse and the healer forums would undergo a nuclear explosion. But by being vague, players assume there must be some sort of logic that the devs see that they don't and merely grumble a little.

If you're going to explain your decisions publically, you need to be able to back up your choices and show you really know what you're talking about. What you say will be examined critically. If you say nothing, there's nothing to examine and no faults in your logic to point out.