Ya, just like real life, defender won't keep tackling, they just keep jockey and wait for the opportunity. Normally I just press X for auto jockey, follow the attacker when they on the sprint. When they slow down and try to get pass you then only you start manual jockey and time the tackle when they are close in, otherwise just keep jockey and keep some distance.

So far, i enjoying the whole new system, especially AI defender wont stick on you when you got the ball on the run toward them on counter attack. They will keep backing up and contain the pitch like real life! Except the goalkeeping. Its really poor AI scripting for goalkeeping.