In TE4 cpu has become more overpowered at the net than it was in T13. I felt this while playing and found the same during cpu vs cpu simulation. According to me the following could be the possible reason.
1. After the recent improvement in animation, the low and high volleys are dealt very easily. The streching animation has given a reach advantage to the net player.
2. After the improvement in AI, the cpu is able to judge high lob much better than earlier releases. As Cpu positions itself better now, the smashes are accurate and strong most times. Cpu also chases down well placed lob far back to baseline.
3. This is the most important point, so I kept it at last. Cpu is able to hit good volleys of returns made with very high top spin imparted. This is the key point which shifts the balance between a defender and a net-rusher. In the current state, even on clay if the net-rusher takes the position at net, the defender is unlikely to beat him.
Nevertheless a great great game though.