@Riot EXP rewards will only reinforce 4-men gank botlane
Why would they gank Top, since they will not earn any bonus EXP. Why would they gank Mid, since it's only one kill and if they have mobility or flash up is almost impossible to score a kill.
Ganking botlane now will be the only viable strategy, since you'll be boosting 2 champions, you the jungler + your support. That will be a mess, because if you don't gank there even when your Bot is winning, you'll know for sure the enemy gank will camp Bot.
I think Riot should add a nerf to kill share EXP pass 2 champions to make more viable ganking Mid or Top