not sure you can build a rugby game around taking conversions!
It's pretty realistic - The modern game (well, for the last 20 years) is all about the boot (unless you're New Zealand). The running game is just to get you in range. They're trialling different points systems to try and change the emphasis back to open play: I watched a game built on a 2pt penalty, 3pt conversion system and it was totally different. More like NFL.
A good kicking system would be a good start: drop in an analogue-stick-only pass and move system and you're on the way. For me the most important thing for a rugby game is to control the direction of play rather than the players directly, if that makes sense: Madden worked this out years ago, making you feel skillful because you're directing play, rather than moving the player (which is kinda boring).