Hey there, great post! I just this year started getting back into League - before I even heard about arcane. They really fixed a lot of the fundamental issues I had with the game. When I left, game lengths averaged around 50 minutes, and were often far above that - extremely strong base tower lazers, teir 2 tower giving shields, dragon and baron essentially just giving gold and some minor stats, and itemization and balancing completely revolving around lategame scaling, because of items like DFG.
Additionally, I only have had a handful of feeders, and they almost always get immediately banned aftwards. Also, the system for remaking games based on leavers/afk is confusing, but once I figured it out is invaluable.