In the finals they will be forced to play a shallow bench, but so will the Warriors due both teams playing at such a frantic speed and I don't mean running and gunning like the Blazers, both teams play faster harder and faster, and most players including some on both teams bench cannot keep up and think fast enough to play.
For example when the Warriors collapse on you in the paint you have less than a sec to get the ball in the right player hands, if your mentally slow chances are you will turn over the ball, players like McRae and even Ian Clark does not have the mental speed to keep up, so players like LeBron, Irving, K Thompson, Curry and Durant have to log in longer mins.
To the Cavs advantage Liggins appear to be able to play at that high pace and fit in just well on defense.