The whole network needs to accept that masterblock like a normal block ;O also the miner needs to complete the hash puzzle in order to create the masterblock in the first place.
Yup but still I need to trust this block is correct :/ I don't know "why" just I don't like the idea. Need to think about it more maybe
How about the argument that since a genesis block is only one block, and there can be an unlimited number of masterblocks, it is easier to verify the genesis block?