I don't think they knew it was an MMO or that it would be coming out for Wii U as well.  Perhaps folks might be holding out for the HD version in Japan, not to mention a more robust and competent online infrastructure - which the Wii U offers and the Wii definitely does not.

DQ is bigger than FF in Japan... I expected more after some games like One Piece or Hokuto selling 500k+.

Right, and this will have much bigger sales in Japan.  It already has a much bigger opening week.  So what's the problem? 

I bet there will be a considerable amount of people who are holding out for the U version.

How much would be good  for a DQ MMO and based on what?

That's what I'm thinking too. 

I think he'll be disappointed with any number.  If it sold a million in these four days he'd have still said that sucks for DQ - you can't get anywhere with these guys, they're just overly pessimistic and negative when it comes to Ninty.  Pezus admitted this.

MMO success is based off how long it remains active . If 1mill had purchased DQX now but only like 200k are playing it months from now, That cannot be counted as a success

I wonder how much the Wii was boosted...

Yeah, I get that impression. We don't have anything to compare for this game, so waiting for SE results and comments is the only parameter. But Pezus normally make realistic predictions. At least on COMG thread.