Can we have some sort of encouragement to play support or fill?
DISCLAIMER: I am Bronze, so everything I say is thus null and void. As everybody on all of my posts has ever said, "Anything works in low elo."
What do people get from fill? They get to play support. What do people get from playing support? They get flamed by their ADC, likely because they don't know how to support. It's the hardest role and the least popular role. I feel like changes should be made to influence more people to choose support. Something like an IP boost, telling how their favorite champion can support, loading screen tips about the importance of supporting, buffs to support champions or support abilities, etc. The honor system supposedly increases IP, so why not have some kind of automated system that judges games and gives bonuses that way?
I quite dislike the support champions and so thus dislike supporting. I got around this by supporting with champions that I like, champions that were not made to be supports. Rammus, Malphite, Anivia, Fiddlesticks, Urgot, etc. From this point, supporting with a champion they like, they can see what supporting is really like then ease into traditional support champions, or be effective with whatever non-support one(s) they're effective with.
I'd say one thing to improve is to make support items more powerful and impactful, and have the players FEEL that impact with more than just gold numbers. Support items are basically just really shit normal items, and from what I've heard, the new Sightstone items are complete crap and not worth getting. Ideas for support bonuses could be 15% damage reduction for tanks (Relic Shield), 15% speed increase for healers (Ancient Coin), and 15% decreased mana costs for pokers (Spellthief's Edge). Some sort of very noticeable stat boost that would almost make it worth getting on a non-support.
Another thing is choice. Supports build pretty much the exact same thing every time with very little need for variation. More stuff like Banner of Command or Zz'Rot Portal. Though one of the problems is that the supports get diddly-squat for gold so they often can't fit these things in their budget. Also, the support items are heavily geared towards tanks, and I believe that tanks are less popular than damage dealers. People always complain about Riven, Vayne, Yasuo, etc. but I never hear complaining about a tank. I don't mean Darius or Garen who are bruisers, I mean Malphite or Rammus who don't focus on damage.
So basically, supporting is hated for good reasons, so fix those reasons to fix the problem.