As mentioned above, you can copy-paste connections, and mass slave groups of blocks using Shift-V.
However, one thing I've noticed is kind of difficult is to do the inverse. Shift-V allows you to connect multiple slaves (purple outline) to a single master (yellow outline), but as of yet there is no way to set multiple masters to a single slave other than 1 at a time.
I think there should be a way to invert all connections on a given block, that way if you need multiple masters on 1 slave block you can use Shift-V to mass connect the masters as slaves to the block they're supposed to be master to, then invert the connection. Or else a method in which you select a block to be slaved and then connect the other blocks as masters (which is the opposite of what the connection system does now)
This would be useful for designing things such as auto-sort storage systems. My station has a room where spare parts are kept, it consists of a single storage block where items are placed, and multiple connected blocks that pull specific items from that center block. Problem is, to get a storage block to pull from another block, the block it is pulling FROM needs to be slaved, which is difficult when you have 100 or so blocks all trying to pull from a single block.