Chess comes in many forms, both with respect to the clock and the board format.
But why don't we have chess tournaments where we play different openings? That is, a certain list of openings is picked (it could be publically announced prior to the tournament, or perhaps a surprise reveal), and then both players play games with those openings (each opening is played twice, once as black, once as white).
This seems like quite a fun thing to do and an obvious extension to the many forms of chess we already have?
What's the drawback?