OpenTK.Utilities (TKU) was/is holding back release of the core library. The core does not rely on TKU's existance and the split would also result in meaningful version numbers which reflect the status of the libraries better. Due to independent release from each other, updates can occur according by namespace. For example: the core will not receive many more modifications after the GL 3.0 bindings are cleaned and merged, TKU will grow differently.
The question is how to proceed with TKU. One way is to follow OOGL's path and provide your own license conditions and repository for each project, the other way is to create a second repository with free write access and agree to a license.