I don’t understand what is dangerous about adding the scope. It’s not forcing if you have a choice, and you do have the choice. By default we show the least possible clutter. And while you may prefer to see it, you do not need the x-height for designing caps.
Personally I was skeptical at first too, but have gotten used to it quite quickly, and I now find it much better to have a lowercase letter typed out next to the cap than to have the line go across the cap.
Ascenders and descenders are not for lowercase only, there are many more purposes, beyond Latin even. That is why we always display them. But x-height? If the x-height is relevant for your cap design, no problem, switch on the scope. But for most designs of most users, I do not see why it should be the default.