The final answer to building SS or not.
TL;DR: building a sighstone is in line with the meta->the best option for supports.
You are not required to build Sight stone but it is imperative that you do The reason why is because each role has a certain thing that they need to do, same thing with champions, and same thing with the overall game. It's called a meta. You build certain things depending on your champion and the role you chose at the start of the game. Sure you can deviate from this path, go ADC vel'koz who the fuck cares if it's a normal, but do not expect to have the best results. A meta ADC would be better.
The same goes for support and sightstone. Sure you can make not having a sightstone work but it is not nearly as good. The meta is defined by what works best and building a sightstone happens to be what is best. This goes for having a tank on your team, having an ADC, and having an AP champ.
