If you add the set pieces from Union and ditch the six tackles, wouldn't you just end up with Union?
There's no need to change. I'm sure the Leaguies are happy with their game and I'm happy with Union.
I take your point about 13 players. One former Irish international, Tony Ward, in a column in a newspaper, said that Union should consider switching to thirteen players as defences have come along a lot since he was playing and this is stifling attacking play and that by reducing the number of players, team will have more space in which to attack. So you're not the only one that's thinking it.
Personally I like the game as it is, but I know in Australia especially, where there is a lot of competition between sports, that ratings are down.