Double Elimination FinalsThe Upper Bracket (UB) team will start off with one “map win” in the Bo5. The UB team will also get to choose 3 of the remaining maps, while the Lower Bracket (LB) will only choose one map for the finals.
For the LB team to win, they need to win three maps, whereas the UB only needs to win two maps (since they start with one win already.)
This completely defeats the purpose of a double elimination bracket. The point of having a double elimination system is that you must lose two matches, where each match is played with identical rulesets, circumstances, etc. In the system described above, the team coming into grand finals from the loser's side does not even have the opportunity to play the winner's side team on an even playing field.
The only other competitive esport I follow is Super Smash Bros. Melee, but I can still draw examples from the game. It is very common to have Player A beat Player B in winners finals, then Player B returns to grand finals with adjustments and adaptations and double eliminates Player A. It is also common that Player B wins the first match of grand finals, then Player A makes their own adjustments/adaptations and defeats Player B in the bracket reset. With the above system, you are essentially removing the value of having the second opportunity that comes with a double elimination bracket, since you come into grand finals with a massive disadvantage, and, even in the case where the loser's team wins, you've removed the opportunity for the winner's team to make their own changes.
I don't see the problem with a standard Bo3 stock double elimination grand finals. It's the only fair system.