I also hated the three-way mind rape. How does that make for a good Star Trek, or a good anything?
I can see how filmmakers considered it essential to what plays out later on. Troi being able to sense the location of the Schimitar, having been in contact with the Viceroy. Turning the tables and using that Betazoid ability, instead of a tech idea like repeating "gotta have a tail pipe" or "ionic pulse brings down the cloak". Then later Riker kicking him off the ship, during their confrontation of course. What's lacking in that plot is, Picard's shocking lack of empathy for Troi after the first assault. Shinzon's earlier deleted scene attempt to reach Troi, appearing to her while she's in the turbolift is creeply effective, and its inclusion in the film would have signalled the more supernatural aspect of what was going on.