Variety is the spice of life. Their individuality is what makes the Senju so special.
If one hears he or she is fighting an Uchiha: you get ready to fight the sharingan, fire style, and their MS techs if they have it.
If one hears he or she is fighting a Hyuga you prepare for the gentle fist.
If one hears he or she is fighting a Senju.....how do you prepare? He or she could be any element, he or she could be a taijutsu user, or he or she could be a genjutsu user! On top of that, one knows that Senju will be extremely talented in whatever it is meaning one has to see what he or she can do and immediately be able to react while devising a counter strategy!