One of the issues I remember seeing raised (don't remember if it was here) is the possibility of people going from server to server scamming. If they have to keep that toon on a server for a significant amount of time then I think it can lessen the damage they can do.
Transferring servers (in my opinion) isn't something that should be done on a whim. We don't know what OTM would have to do in order to make server transfers possible. Not just in general but for each transfer. Being able to just pick up and transfer on a whim could lead to other issues.
Knowing that you'll be on a server for the next 6 months or so would definitely encourage people to do their research and check out servers before transferring.
If you're dedicated to scamming you'll find a way no matter what. Lack of official world transfers isn't deterring any scammers.
We don't know
what OTM has to do to make a server transfer sure, but we know they can do it. How do you think your toon gets onto a beta server? Explain these "other issues" because that's just filler just like we're seeing here with the "devalue muh rares" argument.
6 months is just a ridiculous amount of time. I don't understand how you can believe that is reasonable. I personally believe many people will stay on their servers for more than 6 months if they made an informed decision, but if you make a mistake and are now locked for the next 6 months? People won't play your video game forever.