Its not a rock paper scissor one.
id say the battle mechanics stay as all the other DQ games.
the only difference is how you choose your attacks
You have 2 Attacks per Character/Monster, move which uses A and Move which uses B.
while the attack is being executed you need to Input A or B as the attack tells you to gather Yuuki or Bravery Points.
when you have Maximum Bravery Points you get to see some very Epic Moves executed by the heroes of all DQ games until now, Trust me, i play the arcade only to see these epic moves.
not only that but once in a battle you can use Special cards for Kickass animated attacks.
The downside is that you will see a lot of Akira Toriyama Redundant Graphics in characters :/
Just look at the Male Character, he looks just like Kid Gohan SSJ, note that this is just my personal opinion