It's not 'stronger by design' it has evolved. However most of the components remain intact. Barcelona were beaten because they hadn't the legs in midfield. We may have lost 3-0 in the first leg. However how many teams out possess the best possession based outfit in the world?
However in the game at Anfield, the style changed slightly, it was more crash, bang wallop. Klopp deployed blitzkreig. It was in your face for 90 minutes, however even that has evolved since Klopp first arrived. It is not as fast paced because it's not possible to do so for 90 minutes.
It's more switching through the gears when it's required to do so. It can go from first gear to 3rd gear and then back down to 1st gear in minutes. It's the defensive solidity that allows to switch through those gears.
Klopp calls it more mature with additional discipline and that is where the evolution is. Can it be evolved even further? Of course. It also takes improvisation and intelligence and quick thinking. It is also taking matters into your own hands. That is exactly what Trent did. He wasn't following instructions, he intelligently improvised and it worked.
Something similar happened against Newcastle. Trent was going to take the free, Virgil said no, leave if for Shaq and told Shaq where to deliver it. Shaq delivered and Divock finished. Again that is clever improvisation and taking matters into your own hands. It delivers results. Is this more evolution? Of course.