Hi Larian,
I specced Lae'zel into the Battlemaster subclass and took the menacing attack maneuver. It would not work. Every time I tried to use it, I'd get a "true strike" notification and the attack would miss. Pushing attack works. Rally works but isn't intuitive (the temp HP are displayed as a second bar, not as like a X+Y or something). Riposte seemed OK, but I don't like the implementation of reactions (I'd like to chose if I want to take the reaction, not have it go off at the first trigger).
Also, the 4 on the die never went down until I used my last die. This seems like a bug.
Lastly, but more of a suggestion, the tool tips made it sound like "you can spend a superiority die", as if I'd be able to spend them after the attack (like you can in 5E). I'm assuming the die won't be spent if the attack misses for menacing attack and pushing attack.