I've noticed that this rule only allowed goalkeepers to run to make a break... some still hold the ball after thr 6 seconds, other drop the ball and kill some more time... So why not adapting the rule to 6 seconds indside the penalty box? this would force the goalies to at least play the ball out (and not being able to grab it), and strikers could get the ball more easialy...

This rule is a great rule, and many people do not fully understand it.
The actaul 6 second ruling has been in for a few seasons, and only the 4 steps ruling was removed. The goalkeeper therefore is only allowed to control the ball within his "handling" possession for a maximum of 6 six seconds, the time shall begin once the goalkeeper has opportunity to release the ball, the does not start once he gains possession, basically it starts once he is on his feet and can play the ball. There is no time limit if the goalkeeper has the ball at his feet, and making a rule for this is ludicrious. The only real problem with this rule is that the referee's struggle to get back from the penalty are to about halfway in position for the next phase of play, and being a successful referee i know all about this. The ruling to abandon the 4 steps rule is the only rule to be recently implemented, not the entire 6 seconds ruling, and as i saidf before has been in for a few seasons, if you only read a law book. This ruling has been altered to increase the speed of play which has progressed over the past seasons.