Canishogun will probably be going in at A+ for now, with the potential to drop. Mr.X makes some good points about Cani not being a good sweeper because the moves are 130-160 and retribution is unlikely to be charged on the first turn. However, the high speed is for Cani’s SS which probably passes just the right amount of time for retribution. So if you are using this monster with a good combo then things probably work out well most of the time. Otherwise, the opponent needs to have at least one fire monster or some stun to make Canishogun perform brilliantly. Without a fire monster or stun around then Canishogun performs badly.
So it’s a monster that either needs to be built around carefully or for the opponent to have fire/stun. It has great potential but is not as reliable as you’d like and can die quite easily. In current top teams there isn’t much stun around so all stun converters/counters aren’t as OP as usual, but in a stun meta this monster will obviously be a great pick because stun converter is always strong there.