A 48k power team of baze, chirrut, thrawn, r2, and 5's beat my 68k power sith team (none of which were 7* or max level)... My sith team didn't even kill 1 of the characters in that fight (all of which are 7* and max level)...
Power cannot be the metric used to determine difficulty since clearly synergy of characters can make up for 20k power; nay more so in fact, since if it made up 20k power the team's would have been equal and the one would have barely beat the other (it would have been down to the last character on each side as opposed to a complete wipeout).
Please add/change the metrics in the algorithm that determines the teams we face in GW; make the metrics depend on team synergies too. It's easy. You have a ton of data. You can look up all the times that a team in PvP with 5k or less power that it's opponent beats that opponent. Further you can rule out player skill by looking at both low power AI teams that beat players and low power players that beat AI pvp teams (taking auto-play into account as if it were AI as well).
Seriously power solved nothing.