This 50% rule is the main loophole in DRS or umpire call.
It's not a disadvantage to batters imo, it's just you are empowering the toothless bowlers. When the ball actually kisses the stumps, bails get dislodged it doesn't matter if it's 1%-10$ or so on. You don't say that it's just clipping or batters are in a disadvantage.
So why give benefit of the doubt to umpires and batters when it comes to LBW?
OK.. then maybe we can agree on that. But time is also important. As you mentioned, the bowlers are feeling toothless these days. I just hope that the players will not waste too much time in appealing and reviewing the decisions. From my perspective, the only disadvantage with DRS which I have observed till now is the wastage of time in reviewing the decisions. And in some cases, the players just review them, just for the sake of it. Finding the right balance between 100% accuracy and finishing the matches on time is very important.
Excessive and unnecessary appeals happen all the time and umpires do have complete control over it as they have the right to penalize players or captains, given they have been warned once.
Also when the captains do take review it doesn't take much time as they have only 15 secs to take a DRS call, problems come with the 3rd umpire cause sometimes in pressure moments they even take 2-3 mins.
This is a good video on umpire's call
https://www.youtube.com/watch?v=7MfLv9hqYXM