From my understanding, stellar-core nodes (i.e., including watchers and validators) will arbitrarily connect to other nodes by default (i.e., no preferred peers set). While it makes sense for watcher nodes to connect to validators so they can propagate block/transaction, I cannot think of any reason to let my watcher node connects to another watcher node.
In other words, a peer-to-peer network of non-validator nodes seems to be unnecessary. If I want to catch up with the blockchain, I just directly go to one or more top validators. Why should I care about receiving blocks from other watcher nodes?