The five minute round timer was probably the best feature in this cup and should be considered for the normal ETF2L rule set. Contrary to domos point I believe that it actually offers a lot of much needed comeback potential on maps like Sunshine and Snakewater. These maps are extremely attacker favored to the point where a 6v4 push out of last from the defenders perspective is still a risky fight, assuming the other team knows what they are doing. Domo isn't wrong when he said that holding last for 5 minutes will be very appealing on a smaller round timer: but after having played with Josh, Nubbi and Silentes the past few seasons I believe that the game just offers more tools for attacking than defending, teams just haven't realized it yet.
For the overtime, I think it needs more testing and adjusting. I simply don't see a reason to extend the game past the regular 30 minutes if the score is 4-0 or even 4-1. If you concede this many rounds I believe there is no reason to offer the opportunity to come back, whereas in the prem grand finals this season it would've made sense because the games were close and the momentum shifted back and forth.