Despite saying that he is the strongest, I actually like Tobias the least of the rivals. Too overpowered, IMO. Plus, it seems like he has got no emotion. AT ALL.
And yeah, I also agree with you on the thing with Tobias, because yeah. He was way too overpowered, taking out Ash's entire team with his two Pokémon, who in addition to that were legendary. I really hope he'll make another appearance though, as I kinda wanna see the rest of his team.
The fact that he seemed so emotionless, was probably because he's so used to winning, that it doesn't excite him or come as an suprise anymore, and the only point where he did show some kind of excitement, was when Ash beat his Darkrai. Apart from that we didn't really get to see him that much, or really learn his personality, so there we really didn't have much opportunity to see his emotions anyways.
Anyways, I think it's time for a new topic, if you don't mind me adding.
Which of the rival teams do you like the best?