1. Putting more capacity towards peers that "prove" themselves great routers, closing channels that are "unproductive".
  2. Running experiments with peer selection, especially using betweenness centrality measures.
  3. Hardware resource usage is negligible, personally I had a node with hundreds of channel on a retail i5 laptop. Any mid-range server could probably do thousands of channels.
  4. Private channels can be expensive for a routing node to have, I think they're really best for full-fledged LSPs who are charging the end-user wallet for the private channel.
  5. IMO a day offline is too long, close the channel.
  6. I think it would make sense to have both a clearnet and a tor node.