A brief explanation on how the block rate and therefore latency is affected by replication.
The block rate goes down a bit with higher replication factors because a higher number of replicas are needed to send messages for the block to be agreed upon, and the Distributed Key Generation (DKG) work is more computationally expensive. This shouldn't be very significant yet, but once there are so many replicas that they can't all talk to each other and need to forward messages, the message latency will go up, and this will add a bit to the round time (should be linear in the "hops" of communication in the subnet).