Most certainly the optimal solution would lay at some intersection of batching and broadcast delays. Broadcast delays would take them 5 minutes to implement. Batching? Who knows.
I don't believe that delaying announcing transactions they just constructed would provide any value to the network. It's better to have them out there and provide people with more complete information about them.
Generally the big barrier to deploying batching is delaying the payment (and learning its txid) in the first place.