It ruins the whole "what type is he" at the start, and the fun of predicting what they have: you never know what pokemon they could be using. Why add it now if monotype was fine before?
Pokemon Online Simulator The aim is to replicate what can be played on Pokemon XY. You can't turn off team preview in game so why should you be able to in this tier?
Because somebody wanted it to be a DW tier which was decided arbitrarily three or so years ago to also be No Preview. It was a pointless thing to not have in the tier and the Wifi Battle clause will not be removed. The only reason we kept it last generation was because it was so late by the time anyone brought it up, it'd only serve to annoy the players dedicated to the ladder. Long story short, we're still keeping preview on every tier this gen.