User blog comment:WAFnuke/Fans of LoL giving Inspirations for Riot?/@comment-4593717-20131008132924/@comment-3974211-20131008134108

I'd say (1) and (2) were your only valid reasonings.

With regards to (3) - I honestly believe them when they say they look at every suggestion. It honestly doesn't take 2 seconds to open it and go - no.

With regards to (4) - there have been plenty of fan-submitted skins that have been made a reality, and that number is increasing as Riot grows more confident. The quality of player suggestions is increasing and given that the Riot forums use a rating system - it's easy to tell popular ideas from unpopular ideas.