I played rugby for a year- aint no joke
The tackling is MUCH more fundamental in rugby, because it HAS to be. If you tackle someone improperly in rugby, chances are youre going to injure yourself far more than the other guy. As a result its seen as something of a gentlemen's sport.
That being said, while rugby is a tough sport played, football is a VIOLENT sport. Basically this:
Vs. This
I would have no problem recruiting a rugby player on defense, because of their tackling and pursuit abilities. A rugby player on offense doe?