Nup can't show you numbers or stats, as I said it's just my opinion. But every year the media carry on how there are so many more injuries in the game today, they might be hyping it up? But please show me your numbers with the rates of injuries compared to the interchange rules.
Much like your opinion I can't do that because injuries are incidental to any collision sport and the truth of it is that any numbers won't show a direct link, they are just numbers. They are gonna happen and people, mainly in (but not always from) the media always try to point the finger at something for a story. Was only just a few weeks ago that the panthers and media were trying to draw a link to the worn surface of parra stadium as the cause of an injury to a penrith player, even though there was only one injury.
In my opinion the interchange thing and injuries is just something drummed up by old school players and the media because it's one of those things that gets people taking about how something needs to be changed (most years we also get the thing about how there isn't enough talent in league to support more than 16 teams but also get stories about how there is so much talent drained playing esl. Same thing every year about pre-season leading to so many injuries regardless of the inconsistent amount ).
At the end of it the nrl and the media reporting nrl have never actually provided stats that conclusively back up that restricting interchange lowers injuries. The only organization that I've seen do it is collingwood in the afl (when they went from four players close to unlimited to three players unrestricted with one sub last year), and funnily enough the numbers had a big shift showing the effect of fatigue on injury. While it was only over 2011 it was consistent across the afl and backed up by coaches of the other clubs. Again the numbers may just be coincidental but sports med research has shown that fatigue does play a big part in injury.
Put it this way, apart from blocker whining on the radio about interchange, when it was unrestricted was the product worse? My opinion is no.