Adding some more points to pooya87's answer,
- Have there been any discussions about licensing Bitcoin client versions?
Yes, by satoshi himself back in 2010.
Foremost, the client or a wallet is one which doesn't hold our coins. They securely generate our private keys and store them. For in order to spend the coins, we do it through private keys. Hence you can code your own wallet either as a GUI based or command line based and get your own license. But the original satoshi client (i.e Bitcoin Core) is a free software released under MIT License which allows anyone to modify, run and distribute/redistribute the software. Licensing the core client other than MIT License will hinder the adoption of the project significantly reducing the price also.
- Do you think other licensing will limit alternative customer development?
Yes,licensing the client other than MIT License will limit the adoption and development. satoshi has once spoken about the Licensing of the client and why he doesn't want to go with GPL or other licenses.
If the only library is closed source, then there's a project to make an open source one.
If the only library is GPL, then there's a project to make a non-GPL one.
If the best library is MIT, Boost, new-BSD or public domain, then we can stop re-writing it.
I don't question that GPL is a good license for operating systems, especially since non-GPL code is allowed to interface with the OS. For smaller projects, I think the fear of a closed-source takeover is overdone.
- Will a license reorganization ever happen if Satoshi returns?
No, I believe it doesn't happen since satoshi is not willing to do so. MIT License is very less restrictive when it comes to Free software and hence it is good to continue with MIT itself.
