Maybe decrease gold per enemy killed and increase it for tower destroyed?Well, League isn't about killing though
Its about objectives and map control
i think the problem of support is that the adc thinks the support is its nanny. If they kill something they are good, if support hits the enemy and kills it the. we are kill stealing, if support dies and adc survives we are idiots and feeding the enemy, if the adc dies and sup survives "you fucking idiot need to protect me, learn to play". If both die: "fucking supp it's your fault I'm going afk".
Instead of reinforcing the meta in the way that the adc is the only one that gets support, the sup should be like a line jungle, ganking lines and supporting the 3 of them, maybe an item that ups movement speed when moving between lines but goes down to normal if you deviate from course and start wandering, the item disappears when you reach 20minutes. After the landing phase ends many supps change build anyway.
But that's my opinion, many times I change from mid to support thanks to the whiny kids that want mid, so I end supporting as my mains That have almost no CC and yet build as an hybrid mid-support, end up doing mid's job.