Was it really due to that lawsuit? IIRC the main issue with P2P was that you could discover anyone's IP address by knowing their Skype username. I recall that people used this to DoS people in multiplayer video games - they looked up accounts with roughly the same name as the in-game one and proceeded to drop their connection. It was especially common in League of Legends.

Yep - It was bad enough that it was common practice for people to proxy their skypes through a third party.

(It was pretty nice that Skype let you do that really easily though)