I don't think there is any "rush down trap" in Ethereal. You can block low all day, react to 21U4 or F3, waiting for Mileena to waste 3 bars and the max damage she can do is small chip plus 12% throw (which you can tech as well). The gimmick you get from regular fade can be blown up by many characters. The problem is that ex fade doesn't do chip damage which hurts her pressure game a lot, while Kitana ex glaive does decent chip (I mention mournful as an example). To me, Piercing is still better than Ethereal
Here is the thing that a lot of people don't understand about Ethereal.
Sometimes the threat of your options opens up other options.
For instance, Lets say I start using Ex Fades in my block strings. For example, after something like F24. Well, after that Ex Fade I am left at plus seven. My quickest mid in this situation is a B2 which is 13f. This will crush anything 6f or higher.. However, smart players know that if I do B22, my pressure is essentially over as her ex fade after that is minimally plus. This means I can start doing things like 12,123 staggers, but these options are beat by low pokes due to the high starters. However, if they start tossing out low pokes, they will get crushed by my b22.
See the mind games you get to start playing?
A lot of players will start backdashing as a universal tactic against some of this pressure, but if you gamble with the ex roll mixup (like you said everyone will just block low) you blow both options up.
I find when I play, everyone just respect the fades, and when that happens I usually get a F12B4 Which builds back half of the bar I just spent on the ex fade and gives me a 50/50 within the string.
Her mind games are about what you THINK she is going to do and how you are going to start to counter it. Low blocking everything can lead to 30% of your life being taken away, High blocking everything gives me free pressure, blocking everything in general gives me free throws, and backdashing gets beat by me reading you blocking low...
See the situations here? In every sense she is in control and has options. What's important is that she is left in your face with several plus frames. She is never in that situation in any other variation.