Free realms transfers have been used for years in attempts to balance populations between over- and under-populated realms, sometimes successfully and sometimes not. Many times these free migrations have resulted in huge swings in population balance in the servers involved, and regardless of that fact, most servers are pretty polarized to differing degrees faction-wise.
The question I'm obviously leading to is, why not offer limited free one-way faction changes in a similar model ? I can't imagine it having more or even as many caveats as a one-way realm transfer, even (or especially) for guild transfers. I'd even say leave it open for each server until a balance (within thresholds) is reached.
Am I missing an obvious reason this would be an awful idea? Because I can't fathom one. Obviously this has more impact on PVP realms, both positive and potentially negative that may have to be worked around. Hell, best case I think maybe it could help revitalize world PVP over a length of time.
I'd like to post this on the bnet forums, but I haven't been able to pay for a sub for several months.