Balance change ideas (at least try them riot)

The main problem I see with the balancing in League is partly in the abilities champs are ALLOWED to have, and the other part is the items you can buy for your champ. If someone figures out how to proper abuse their champ the game is already over once they get those items. So why doesn't riot restrict certain items for certain champs, I'm okay with people building off meta items along as they don't make that champ OP. In addition riot already has items that are restricted to melee and ranged champs and masteries that are less effective depending on wether you are ranged or melee. How about it riot can you at least try this method or is it too much work cause quite frankly you were already bad at balancing from the beginning.