Recalculate kill gold
Someone shouldn't get kill credit if a turret finished them off after you're dead you should get an assist on an execute (or something like that).
The amount of gold you receive for participating in a kill should be recalculated.
Some kind of formula that takes into account amount of: damage to the target, damage taken from the target, healing done to the target while you're engaged, healing you received while engaged, CC you received while engaged, amount of CC you placed on the target while engaged.
The way it's been since launch assists and "last hits/last to hit before turret kills them" for the kill doesn't really reflect the appropriate reward for your effort.