Thanks for the suggestion! I thought of that, but when you want to generate a weekly report showing the performance of MQLs handed off to the sales team and you have 25 reps, that's a really, really cumbersome way to do it... which made me wonder, why can I group the leads in the report by state, by ZIP, by city, by status, by source, by anything, but not by owner?
I did find a less cumbersome useful solutions in this thread: https://community.marketo.com/marketodiscussiondetail?id=90650000000PGldAAG which works - create a dummy lead owner field for reporting, and set up batch & trigger campaigns to populate and update it with the lead owner name, and then sort by that (which you can do).
I do love Marketo but this is such a bizarre omission, especially when the documentation on lead performance reports breezily tells you that you can group by any lead attribute. Well, no, actually you can't.
But I highly recommend the above solution, and appreciate you taking the time to make a suggestion. What you're saying works for digging into a single rep's activity for sure, just very time consuming when you have regular reporting on a larger salesforce.
Cheers!