I was wondering this after training today. On returning a good a smash I was always thought it more beneficial to attempt a tight net shot in order to try turn the attack away from your opponents. In the old scoring system this was probably okay but under the new scoring system is this now seen as a low percentage shot, as it needs to be so tight it makes the shot tougher and so may bring more errors. Under the new scoring system are good defensive lift returns a more advisable option when the partnership are pretty competent defensively.
I don't think anything has really changed. You still win points by winning rallies; it's just that the "feedback" from winning a rally is a little more immediate now. Regardless of the scoring system, you need to choose good defensive shots. If you are totally reliant on one type of shot, then your defence will be shaky. The general idea is that you use counter-attacking shots (blocks, pushes, and drives) whenever you feel the front player will not be able to cut them out. However, when your opponents are in an especially good attacking position and are able to put more pressure on your defence, it will be difficult to control these counter-attacking shots and therefore the risk of their being intercepted is high. In this situation, rather than play a bad counter-attacking shot, you play a good lift, and look for the next chance to counter-attack. When you are under extreme pressure, this rule often gets reversed: because you now don't even have enough reaction time to play a lift, you just stick your racket out and try to block the shuttle (preferably away from the front player). But this is desperation defence. You can read more about this subject in my doubles tactics article. Specifically, you may want to look at choosing defensive shots and choosing defensive angles.
If you can win a match with the old scoring system, I don't see why you can't win the same match with the new scoring system. I find it pretty much the same except games are shorter
