I've been thinking about this issue of possible lightning network centralization. I think we might be able to use some simple math to get an idea of how centralized or not the network is becoming.

1. Perfect centralization
   If all nodes are connected to one centralized node and "n" is the number of nodes, the number of connections is (n-1)

2. Perfect decentralization
   If all nodes are connected to all other nodes and "n" is the number of nodes, the number of connections is n(n-1)/2

So at the time of writing this, there are 194 nodes and 520 connection.

Therefore, if perfectly centralized there would be 193 connection and perfectly decentralized there would be 18,721 connections.

Not sure how helpful that is, but I like metrics, so there you are... ;)