How would I explain SegWit to a non-technical friend? How can I explain the potential ease of scaling and feature benefits of Segregated Witness to a non technical friend?

How can I explain the potential drawbacks of Segregated Witness in a non technical manner?
The name itself is a good hint as to what it actually does.

What we have today is a "witness" (i.e signature scripts) included in every Bitcoin transaction in non-segwit compliant transactions. This allows every full node within the Bitcoin network to verify the integrity of any transactions. 

By removing the signatures in a Bitcoin transaction, you lose the ability to verify the integrity of the transaction. But in reality, not everyone needs to be able to independently verify the integrity of a transaction.

Thus, by segregating the signature from a transaction, we have a smaller transaction that describes the inputs and outputs exactly as it is. But if you want to know for sure that these are verified inputs, you'll look up the Segregated Witness set to find the corresponding scripts to validate the SegWit Transaction.