For people obsessed with release clauses this will probably be a good news but from what I've read in Chumi's case his contract is for 2+3 years and I guess it will only be extended in 2020 if he'll be promoted to the first team (didn't really watch him enough to say how talented he is but I don't think he was every highly rated so chances for that to happen are probably very low) or he'll want to stay in Barça B/go on loan,.... If not he could still leave on a free so in reality his 100M clause will only be valid for the next season.
Other players contracts (Oriol B., Ruiz, Miranda,...) will probably be structured in similar way.
Another thing: correct me if I'm wrong but I think we can only insert higher clauses when players are 18 so younger players will still have lower clauses. Those will apparently also be raised from 3M to 6M but this won't prevent kids leaving.
We also can't forget that players/their agents have to agree to higher clauses and not everyone will do that. So while this new policy looks good in theory we will still only protect players that are old enough to sign professional contracts and want to stay at the club (so they will sign contracts with higher clauses) but those most vulnerable - 16,17 year old kids who are not fully commited to the club - will still leave but at least we'll get a bit more for them.
And I'm ok with that. We should concentrate on keeping players whose goal is to succeed at Barça and not waste our time and money to convince those who want to leave.