Date format should be consistent, and should be formatted within RE, not based on the regional settings of the user's computer.
The date format on my system is 08-Mar-2013. In RE, the date in the gift record is 08-03-2013. Other dates such as constituent code are 08-Mar-2013. The gift date format cannot be changed.
I am fairly certain the variations you are seeing are due to the differences with real dates and fuzzy dates. Constituent codes dates are fuzzy dates and allow for just a year, etc.
It can be cumbersome to change back and forth and some users do not even have access to those system setting (per IT security).
I am not sure where your variations are coming from, but I agree that the RE date based on system settings isn't always best. And it isn't just date, also the way Word will round gift amounts if you are using a mail merge from RE are based on system settings. My overall preferred format may not be my preferred format when using a certain function, so I understand where you are coming from.
I am still fairly certain this has to do with Fuzzy dates vs "real" date fields.