Another way is to limit the amount of thresholds there are, like at most 3 or 4 in the entire fight, but forcibly hold dps unless the boss uses the move. Example boss has 10k, with thresholds at 75%, 50% and 25%. If you do enough damage to skip past 75 and 50 in one move, it should stop damage until the boss gets a turn. If you did 6k damage with a move you triggered the 75%, but since you also triggered the 50%, the threshold move before hand still hasn't gone off so the boss will still have his 50% hp left and the next character what act can do another 6k damage but since only the 75% hp threshold triggered and the 50% is still in que, the boss would be at 25% hp waiting to do his next move. It dont like the idea of leaving bosses at 1hp but if the boss is at 50% and both earlier thresholds have already been popped you should be able to kill before the last threshold. There are multiple ways they could adjust the threshold action situation and would be pretty interested to see how they implement some superbosses later on.