I absolutely agree with Kenny and Sanford. I would not use queues, though, since contacts cannot be added to queues and that would still create duplicates. You could assign records that are pre-MQL to a designated (non-sales?) user so that are not clogging sales but are still visible when searched in SFDC. You could the build MQL assignment in Marketo or in SFDC.
Thanks Alex. That was exactly our plan. We are assigning all leads below a certain score to an admin (non-sales) user and then building an assignment flow that would trigger when the lead hit the appropriate score. I appreciate the input!
For duplicate management, the best practice is to sync all leads to Salesforce with the MQLs being synced to a queue.
RingLead's Unique Entry manual entry Salesforce app would alert the phone agents as they were entering data from the call in Lead was already in Salesforce.
The agent could simply click on the existing record and go on their way, without creating a duplicate that would get sync'd back to marketo
RingLead's Marketo webhook would prevent the web form dupes (Lead or Contact, RingLead can even create route Leads to existing Accounts).
The two leads, two salespeople situation you describe is terribly damaging to Sales' trust in Marketing. The second the sales people start saying "...these Leads suck" us marketers are done.
If you care to chat, email me at email@example.com. RingLead helps more Marketo customers optimize their data than any other partner. You are not alone, the challenge you describe plagues most of your fellow Marketo users.