Viewing cached lookups on FTL would be helpful in tracking general end user web usage. Top Domains shows us the top 10 domains but seems a bit short of the job if most of the domains listed there are really sub-domains from the same company. My top 10 is usually filled with *.google.com or *.microsoft.com (clients4.google.com, play.google.com, android.clients.google.com).
Expandable lists that start with TLDs and move to domains followed by sub-domains can give a quick overview of locations that were potentially visited. Microsoft's DNS Management does a good job of showing this idea.
The ability to clear the entry could help when troubleshooting split DNS problems or when using dynamic DNS sites, but is admittedly less useful.
At home it would be nice to scan through all cached domains for games sites (if the kids are grounded) or porn (once the kids are older) .