This seems like a no brainer, as it adds no value to the Marketing team to see the GUID of all the synced Lookup fields from the Dynamics CRM integration with CRM.
So, to see an actual value, well, it makes 100% difference in the product.
Having just implemented Marketo with DCRM, we are seeing this same issue. It's limiting our ability to create the smart lists and run the reports we had planned on when we were told that Marketo integrates with Dynamics (which is half true it seems). I voted this up and hope to see a fix very soon.
A complete hands down need for us. We use lots of lookups across Marketo-synced entities and to have to create sister fields and populating workflows is nuts.