Yea, the stamina bar is a must, otherwise there is no defense. How could you lose if you're able to throw an endless combo until the opponent dies. Plus it would be a good idea to be able to throw a counter attack that does like double damage if you're able to duck a punch and then punch while still in the duck to do the counter. Otherwise you just ducked a punch but it doesn't matter or change anything about the fight.
Agreed on all points. The duck is actually being improved on to allow counter with an uppercut if the opponent whiffs. (It's on the To Do list) Until then, duck is just to showboat/flex.
But as an alternative, you can parry an attack then punch. A successful parry makes you recover faster than the opponent and gives you the chance to counter.