ITT: No one can do math.
Before patch 5.3:
+6 to 8 out of 10 players buy sweepers. 2 to 4 players (the ADCs and maybe some junglers) buy blue trinket to check bushes or chase. 2 players (the supports) buy Sightstone.
+Wards on the field at any point: 6, three for each team. Support can only place 3-5 wards per back depending on the upgrade to Ruby: dropping wards four and five replace the first and second dropped wards because each player is permitted only 3 stealth wards on the field at any point.
+Sweepers on the field: 6-8.
After patch 5.3:
+10/10 players buy sweepers out of fear that the new yellow upgrade means twice as many wards. 2 players (the supports) buy Sightstone.
+Wards on the field at any point: 6, three for each team. Support can only place 3-5 wards per back depending on the upgrade to Ruby: dropping wards four and five replace the first and second dropped wards because each player is permitted only 3 stealth wards on the field at any point.
+Sweepers on the field: 10.
Look at what changed in terms of vision?
Nothing. We're all still facechecking bushes and jungles because denying the enemy vision is somehow more important than giving your teammates vision and helping out your support, whose running ragged trying to put down wards and save your hides in teamfights.
Good job guys.