Tackles are made by pressing one of two buttons; one gives a diving, standard tackle for use when you're chasing someone or drifting across, the other for power tackles. It's not just the big shoulder charges like in WCR, but there are numerous dump/driving animations as well. The cool thing is, you could be running straight at someone, they start to dump tackle you (and, if it's a person, probably feeling a bit cocky) only for you to offload the ball to a supporting player who can happily skip away.
RC2006 doesn't have any set plays (neither attacking or defensive), but then, it's not a simulation. It's a pick up and play arcade game. When I went down to the Swordfish studios, the feeling seemed to be that a small company like Swordfish wouldn't be able to compete with EA if both were putting together ultra-realistic sims. Swordfish just doesn't have the resources. What they've done instead is go for a more entertaining, faster game.