As E3 arrives closer, the amount of rumors just keep on coming. A breif summary of the rumor.

Third-parties studios are starting to receive Wii U "Blu-ray" readers, writers, and discs
Nintendo's requests is that demos at E3 are to be on discs, as
The equipment had a bit of delay in arriving which made some devs wait for a few weeks since they didn't come together with the latest dev kits
The latest dev kits still dont have a dis drive inside.
No talk of 50GB discs capacity
Wii U units at E3 will be sporting drives
Wii U games were developed on dev kits linked to a host pc (running the SDK, the development tools, etc.)
it's possible the access/loading times were emulated
Wii U dev kit have stayed mostly the same size unlike the Wii dev kits
future dev kit versions could have the disc drive included inside the hardware