I think a player should have their own style , which is why you book them surley otherwise we could clone Dj's ?
Having said that it is good to have an appreciation of what might encourage poeple to dance. Nothing worse than playing tunes that people just can't dance to, it being a complete set of ballads ( i have suffered this and wanted to make a sharp exit after feeling pretty depressed and almost sleepy ) or a constant " too fast "set can be just as bad and have you reaching for the asprin and a quiet corner.
For me tempos have to be mixed to make it enjoyable and exciting.
Another thing I will mention if every dj played what was popular and they all had the top ten current biggies , wouldn't life be boring after a month or two of hearing them everywhere. This can apply to newer sounds too .Working the floor in this way means anyone could do it if they had a big chequebook . Easiest thing in the world playing tried and tested material.
I admire the person that listens in their own right to a wide variety of material from a wide variety of sources and selects to share with others something that they believe in.
So I vote for individuality and encourage the dj to play for him/her self , show me their choice of play and if I don't like it I just don't make the effort in attending functions that they play at ...or skip their set , you normaly find more than one dj is on so take a break while they are on.