Just my thoughts:

The servers are in completely different geological locations. Transferring them would be like mailing a flash drive from San Francisco to France (or wherever they're mainly based in over at EU), upload the information, and make it available to your EU account.

That's assuming they can't use some electronic transfer, but the servers in the US versus EU are not connected to make a simple $30 Paid Transfer.

I bet they could do it if they really really really REALLLLLLY wanted to. But I bet it'd be a huge pain and would require way more work than should be necessary. Assuming that their databases are, essentially, the same (same structure, tables, etc) I bet they could find a way to create a data dump of your entire character and then import to the other region. The amount of work necessary would probably not be worth the effort - and that's assuming that it's easy to do.

Throw in any localization issues, -endian issues, or anything like that with (or within) the databases and you've got a scripting nightmare. Plus you'd have to disallow transfers during downtimes on either side and the like as well. They probably don't feel there are anywhere near enough players who rolled "on the wrong side of the pond" to warrant the manhours, unfortunately.

Because it'd take the characters too long to learn to speak with the correct accents...

EU server data is all in the metric system

You deserve an internet for that comment, lonewolf. +1 indeed.

Actually, the software is keyed to various regions. As in, you couldn't set up a new account with the CD keys from the US in EU either. I think the EULA and ToS may be slightly different too. Different laws and restrictions apply.

In short, technically it would be no big deal (change cd keys, copy a small amount of data, good luck), but politically you have to be in that region and be subject to that region's rules and regulations, etc., blah, blah, or some such, which is more red tape than you can imagine.

I bet for $50 per character, they'll figure out how.