Aren't her powers over probability? How plausible is it that she can one shot every bot in her path?
Think about what you are saying...
I have, and how probable is it she could essentially bat (to use a baseball term) 1000 every time she fought an Ultron bot? In the comics, I seem to recall them combining her mutant power with magic to increase her effectiveness. The "hex bolt". In a later edition of X-Men ( I don't recall which), they had Wanda constantly think about math (calculating her effectiveness) before deploying her power.
Unless her powers in the MCU are not probability and instead are just telekinesis. Which seems more probable, from the way Whedon did it. Hahaha