Agreed. Let's keep current names. When we add additional subtypes of rollup, we can start adding more fine-grained measurements. I.e.: once we add 'ComplexRollup' we'll have a timer for the superset of ComplexRollup and BasicRollup operations, and one timer for each of those two.

For example, for us today in production we'd actually need to update nagios configs to look to the new string value, were we to make these changes. I think it's bad practice for us to make that sort of change in a minor version update.