Been discussed a lot of times. Not going to happen.
Those 'top five' might not be to every ones tastes. Would prompt a lot of 'Why pick Mod A, when Mod B does the same thing, but also does this'
They may require third party programs such as Mod Managers, Script Extenders etc and those aren't permitted on consoles (The script extenders access the exe, which on a console is a no-no) and the mods won't work without them.
Beth would have to check the mods out. They'd have to check for content (No advlt or copyrighted stuff), for conflicts with other mods, they'd have to bug fix and polish them until the meet the much tighter Q&A standards of DLC, they'd have to package them for console use and then they'd have to pass them onto Microsoft and Sony for them to OK.
And at the minute, both MS and Sony won't allow custom content on the consoles when dealing with a game of this scale (The mods are intergrated to the main world rather than separate maps lile Halo and UT3)
Also, none of the work Bethesda need to do would really allow them to do it for free. So they'd either make a loss for no gain, or they'd charge console owners to use mods.