It's not a low priority but it's not one of the highest priorities at the moment. I doubt we'll ever have something that keeps a 100% accurate uptime record of every individual website because something like that just isn't cost effective to provide for everyone and there are third-party services that can do the job well.
Uptime statistics are a nice showcase of a service but actually keeping the service running smoothly in the first place is always going to take precedence for us.
The statistics we provided for many years were drawn directly from the service monitoring system we use internally to keep things running but as such it is relatively general and does not reflect downtime due to small server misconfigurations that may only affect a few people and it does not report most network outages since it runs on the same network as most of our servers. Those statistics were taken off of our web panel because a lot of people expected them to reflect everything and it caused confusion.
- DreamHost Head Honcho/Founder