The reason split pushing is so garbage now

1. Towers are incredibly hard to kill early. However, it is understandable. You don't want heavy snowball from turret golds.
2. Towers are garbage. They do so little damage that tower diving isn't risky any more. Split pushing used to work cause the rest of the team could turtle in the turret. But now, the turret is just a structure. it offers minimal protection. so a 3v4 or a 4v5, expect a turret damage.
3. Hauntzer tanking 23 shots from NEXUS turrets shows how useless these "protectors" are.
4. Late game, turrets are so easy broken down that splitpushing is impossible. one wave is enough for a team to take turret nowadays.

solution:

1. if someone decides to roam, make it costly. make turrets take more dmg when no allied champ is around
2. INCREASE the damn damage (dmg- first/second turret > (inhib turrets) true dmg-> (nexus turrets)%health dmg)
3. tank busting elements to turrets a must, maybe even give them magic dmg
4. increase their strengths late game.