I have a couple monster-length email threads with Anet's support from trying to link my original Guild Wars with my GW2. The real challenge was getting it so that one account could have GW1, GW2, and website/forums access at the same time. I just got the 'final' email that they're giving up on ever getting it right, haha.
The one positive nugget here is:
"As for your account linking issue, we will soon be allowing players to adjust the linking of accounts themselves. Due to this, for the time being, we are no longer unlinking or linking accounts. We will be allowing players to make these changes before the game even launches."
So, DIY account linking is coming soon™
As it stands, I can play GW1 and GW2. It's just website and forums that's broken for me, and as long as I don't need support, I'll be fine.
The linking of GW1 and GW2, honestly if you don't have a good HoM or character names you really want to carry over, I urge you to just leave them unlinked.