You're not the first one to ask about more granular data.
Based on the Monitor 5 feedback
we've changed our default aggregation intervals in Veeam ONE v6, so right now we are displaying data in a more granular way than vCenter Server can currently show.
Btw, could you please tell me which counters should be collected in a more granular way (in your opinion)? What aggregation intervals would you like to have? Also what is the size of your infrastructure? How many hosts/VMs/datastores do you have?