While considering the block to be gated, one has to see the total current drawn by the block. Each switch offers a certain resistance which will impacts the IR drop, a trade-off needs to be done here so that the IR drop is within the limit.
Other parameters to be seen are the rush current during turn-on and the turn-on time. Typically paired switches (one of lower resistance and the other of higher resistance) are used to reduce the rush current and keep the IR drop low after the block is turned on. Number of switches impact the turn on time as the switches are activated in a sequential manner.