I think in Kabuto itself Tendou seemed to prefer protecting people from afar, but my memory of the series is a bit fuzzy. I'm a sap for siblings, really.

Yuusuke standing around is more interesting than Tsukasa standing around. I don't know. I think even a mysterious semi-amnesiac should leave some impression on me. Daiki is just as mysterious, and I have a grasp of what he does with himself in his offscreen time. It's not painful watching Tsukasa, but it really does annoy me I can't figure out what makes him tick as a character yet.