Riot: Please Remove Sightstone
Riot's balancing team believes that the vision game is everyone's responsibility. This is why they brought in trinkets and created limits to how much 1 champion can ward.
That's why I believe that Sightstone should be removed from the game. Majority of the vision game is still primarily played by Supports (and sometimes junglers) and they are still expected to buy a Sightstone to keep vision up for the team.
This then limits the champion pool and variety someone playing in support can bring. Top, Mid and Jungle can have AD Carries, AP Mages, Assassins, Tanks, Bruisers, Supports/Utility champions. This covers pretty much every champion. Supports are usually limited to a few AP mages, utility and tanky champions.
I believe Riot has done a great job at giving more gold to Supports without any farm and by giving supports freedom to itemize for their particular champion would go a long way in adding a more diverse champion pool in the support role.
My solution is simple: Let vision become 100% every single person's responsibility. Remove sightstone and buff up the trinket wards (after the level 8-10 mark giving ganking junglers a chance to gank still) to the point that all 5 champions can now provide the same kind of vision and vision denial that a Sightstone/red trinket support would provide.
This would then free the support from having to forcefully build a Sightstone thus losing the 800g they could have spent on another item that would give them more relevant stats than health.
Furthermore, I think the side effect of this change would make the ADC role more diverse as well! Currently ADCs are always... well AD carries! We could finally be able to have a say Cassiopeia and Pantheon bot combo without forcing the pantheon to invest 800g in a Sightstone which would heavily reduce his early game damage powerspike by not being able to build AD.
Let me know what you think and hopefully someone from Riot can comment or even better implement something like this! Would make support a lot more fun than it already is for me :)
tl;dr Remove Sightstone and buff trinkets about the same time Sightstone is bought by a support to improve champion diversity in the support role and making vision game truly a team effort.