It's Riot's and our job to ease the learning curve for new players
League has to be one of the most unfriendly games for new players I have ever seen. This can partly be explained by how easy and simple LoL superficially looks while being dazingly complex when you peek a bit deeper. The game has also come such a long way with layer upon layer upon layer of gameplay being added to it. It's understandable that this might be overwhelming for a lot of people, people that might lose interest because of it.
With that in mind it is absolutely important that League gets a tutorial which reflects the complexity of its main gameplay. As it stands a new player knows hardly anything about the less obvious mechanics of the game. That issue is partly ameliorated by the large amount of excellent guides and tips which the LoL community has provided. Some of that knowledge has simply to be learned by experience. Discovering things on our own is part of the fun after all and it's something we all had to do. That doesn't mean however that there is no profit to be gained from a vastly improved tutorial.
That doesn't even require Riot do to do all the work. I suggest Riot puts the community to work to accumulate all the ideas/tips/tricks which we think a new player should know about. This can ( and in my opinion also should) go pretty far. If the community thinks a new player should be aware of for example kiting, or split pushing, or basic knowledge about item building, or wave control, or ... etc. then it might be beneficial if Riot provided the learning grounds for these mechanics. The tutorial can be divided in several smaller tutorials which players gain access to as they lvl up/ play games. This would prevent too much information in one go for newer players and also means that you don't get thrown face first in an hour long tutorial.
I know nobody likes overly long tutorials. But I firmly believe that new players will have a much better experience while leveling up when they are simply better prepared and can start practicing the fine nuances of the game a lot earlier. That's partly the responsibility of each individual, but also partly the responsibility of Riot and the community.