I would like to see more data centers make use of large-scale Oil Immersion-Cooling. I feel like the fresh water use for cooling is a huge issue.
https://dgtlinfra.com/data-center-water-usage/
https://datacenters.microsoft.com/sustainability/efficiency/
Oil might be able to carry more heat but it's more expensive to use.
Oil immersion is something nerds like to think is amazing but it's just a pain in the ass for negligible benefits. Imagine the annoyance of doing maintenance.