Legalising pulling down the maul in the Aussie Championship last year, as Lee says, ended all mauling from further out than 5m. The only thing to add, is that I didn't see many teams even attempting to maul, and the big question mark is was this just an Australian reticence to attempt to maul under these laws, or was it because they knew they wouldn't make any ground?

Personally, I am firmly against this law but interested in the motivations for why the IRB are trialling it.

As far as I can ascertain, it is probably to try and achieve 2 things:

1. Simplifying the game for ref and spectator.
By legalising the maul collapse, the ref no longer needs to make a judgement call about whether the collapse was a deliberate effort by the opposition or just bad technique by the attacking team. Simplifying the game was one of the core reasons for trialling the ELVs (and the other ones so far have pretty much all failed to do so) so I imagine this is a key reason for them trialling this.

2. Reducing the prevalence of the so-called unstoppable rolling maul.
It is admittedly very hard to defend against, especially from 5m out. This law, coupled with the no matching of numbers, is probably intended to significantly reduce the effectiveness of driving from an attacking 5m lineout.

As far as the no matching of numbers at lineout time goes it was probably motivated for these reasons:

1. Removing annoying free kicks for numbers, and making the ref's and spectator's job easier by removing the onus to track the number of fellas in the two lines.

2. Engouraging more long lineouts and more contest for the ball at lineouts, thus drawing in more defenders and creating space for the backs.
I guess they hope this will happen because taking a short lineout becomes a riskier proposition if the opposition are allowed to commit more numbers to the lineout. Whether this occurs in practice remains to be seen (I expect defenders may instead just choose not to contest lineouts at all and simply create an impregnable wall of defenders all the way across the field with a couple of maul-pulling-down experts facing the opposition lineout!)

I guess the lineout will be deemed to have formed as soon as 2 or more players arrive from each team, so it may be messier than it used to be, with the defending team running players over and the attacking team throwing in before two lines are fully present?! Or perhaps the captains will have to communicate the numbers they are committing to the lineout, before it is deemed to have formed, in which case we will still have a counting exercise. I just see this making lineouts scrappier more chaotic and harder for the players, but I am only speculating and could be proven wrong as I was with some of the other ELVs.

I think the desire to simplify the laws of these plays is laudable. But I don't think pulling down the maul is the way to go, and my jury is out on whether unmatched lineout numbers is a good idea.

Personally I am also not a huge fan of the free kicks instead of penalties, and if the whole motivation for this is to reduce the number of rolling mauls from lineouts 5m out, why don't they consider something like this crazy idea:

Have long arm penalties for all infringements, but make it a throw in to the opposition from any resultant lineout as it used to be in the good old days!

This would simplify the game and also make it easier to ref because there'd only be one type of penalty at the breakdown. This would remove those lineouts from 5m out completely. It would also encourage teams to tap and scrum more because kicking for touch would be a concession of possession.

So crazy it just might work!