I think there's enough agreement around the game to reduce the number of interchanges, but I think that there's a bit of overkill about big players - I like watching the likes of George Burgess charge into the defence. I have no problem reducing their impact to a degree, but not simply replacing impact players with workhorses. So reduce interchanges, but just by 2.
Getting wrestling reduced can be largely done by of refs calling held earlier and enforcing it better. The number of times you hear the ref call held and yet players do not immediately stop wrestling is ridiculous, and other times refs don't call held when its clear to all that its the defenders keeping the tackle going.
Apart from wrestling the biggest problem with the game as a spectacle is the conservative 6th tackle plays in attack leading to repetitive patterns in games. You either have to incentivise passing movements, which is difficult, or penalise 'defensive' attacking kicks that don't come off to the extent that players are dioscouraged from using them.
One idea would make grounding an opposition kick in-goal should result in a 20m restart to the defence, similar to RU (possibly just for those made within 10m of the line). The reward from grubber kicks is potentially huge, but how many are really a very negative tactic simply aimed at getting a repeat set?
The high kick to the corner poses virtually no risk to the attacking side so long as they cover any possible breaks, and so has become the 'go to' play. A change which could help provide balance here would be to have a 20m restart for any kick in the air caught within the 20m. At least then the average downside for the defending team is improved.
If the effectiveness of these sort of kicks were reduced, perhaps you could offer a carrot to attacking passing moves by allowing an extra tackle if someone is held up over the line on any tackle (apart from the last)?
The hardest thing with rule changes is looking at the unforeseen consequences. I think its generally agreed what we don't want (although I reckon a hell of a lot of pro coaches don't want any rule changes) but a lot harder to predict what might happen if we tinker around too much.