The issue is that the traits are shown in different areas. You can see them in the trait tree, and you can see them in the unit screen. In the unit info window they are rolled up so you only see the highest level one. In the trait tree you can view them all.
In the trait tree it is ideal to see "Ignores 25% of the victim's defense"
In the unit pane its ideal to see "Ignores a total of 75% of a victims defense"
Either way we switch it isn't ideal in the other case. The possible solutions for this are:
1. Keep it as is (which can be confusing understanding exactly what the traits do in the unit screen.
2. Extend the descriptions as Mqpiffle suggests "Ignores 20% (75% total) of the victim's defense" which could be confusing in the trait tree (for casual players who havent read this thread and understand what it is trying to tell them).
3. Dont have these sorts of traits hide when upgraded. Show all 3 levels of shadow strike 1, 2 and 3 on the unit screen.
Im leaning toward option 3 as the most clear depiction of what is happening. What do you guys think?
ps: you cant ignore more than 100% of a victims defense, 100% armor piercing and 300% armor piercing are the same thing.