If you don't rely on the Bridge Officer bar at the bottom and just use the power bars, you cannot distinguish between two versions of the same power at different ranks. But it would certainly be helpful to know if you are clicking on Engineering Team 3 or Engineering Team 1 when you try to heal an ally, or decide whether to use Attack Pattern Beta III or Attack Pattern Beta I during an alpha strike.
For example, Engineering Team has a "+" in its symbol. Simply make it ++ for rank 2, and +++ for rank 3. Other icons have similar symbols that could be used that way.