Lores and their potential.
It is apparent that the community has noticed how well the newer event was made (and seems to appreciate it), the rewrites on miss fortune's and gangplank's reworks, the interactions netween them, graves and twisted fate and the new game mode (which was a part of the overall event).
To be frank I acknowledge riot's actual effort spent on writting this new story and that it is actually pretty well written compared to some others. I will go as far as to say it actually MOTIVATED me to play gangplank and twisted fate, it even motivated me spending some RP to buy a skin on each!
See what a well written backstory can achieve riot? What if you tried doing some sort of massive lore rewrite on everyone? what if everyone could have cool backstories? what if LOL could be more than just a very popular MOBA? I am pretty sure more and more people would be motivated to spend RP on champions whoms backstories relate to them.
You know riot, you might already know this, gameplay is not the only reason to spend money on a champ. People sometimes spend money on champions because of their designs or other unique attributes. Adding well written backstories on champions might even attract more players who might relate to said champions. Riot takes their advertising seriously, i am pretty sure some kid out there could potentially take up league of legends solely because they came up a champion with a really good backstory to which they can relate, it has happened in the past, and your lores were not nearly as good as they seem to be getting with the new story revolving around tf, graves, gp and mf and even that story could have been A LOT better.
All in all, spend more effort in your lores please, they have marketing potential (not like i am a marketing expert but i can tell a thing or two).