Yes, but in the same fashion, the level of equipment doesn't tell you much either. The "real power level" is not something that can be measured in one number.
There are several things that play into how well a player does in endgame content:
- champion points
- equipment
- skill setup
- compatibility with other players
- knowledge of the content
- player experience
All of these combined will decide if a player will be helpful or just a dead weight in a dungeon, so just pressing the power level into one number that barely represents the state of the equipment is not really useful to anyone.
For example a player can have 501CP, end game equipment and the perfect skill setup, but if they have no experience playing with that character, they will be absolutely useless in a dungeon.
Besides, even if we do generate a number, you somehow have transport it form playerA to playerB - most likely via chat - and you cannot prevent a player from manipulating it before sending it.