The PVP lag is caused by the connection, not by the animations.
The data is sent when you press spacebar.
If the data is sent whenever playing cards/using skills, this can be improved. maybe.
No, it would make no difference or would be much worse.
When you finish your play, you send a single package of information with your played cards, skills, etc. As the lag is caused in the "send-receive" phase and not in the movement processing time, it would take the same time to process each movement package than sending the actual one when you finish your play.
I don't think the connection part of the game is gonna have an update at all.