How many units do games like Call of Duty, Assassins Creed 4, Arkham Origins, Watch Dogs need to sell on Wii U to be considered a success? Will Activision/Ubisoft/Warner be content with 500k-1million units or are they expecting 3+ million sales like PS360 are each likely to have?

Approximately 30% more than Nintendo's best selling game on the system.

They'd be morons if they expected any next gen console to reach software sales that high. I thinl 500K-1 mil is more than enough.

Ya I hope they have realistic expectations since those series dont have an established fanbase on Nintendo consoles. This year they could see 500k-1million, next years installments sell 1-2 million, then 2+ million for the next 2-3 years.

I'd say the games like Assassin's Creed and Watch Dogs need to be looking at around 800-1mil to be successful.

500k-1000k doesn't seem very realistic (at least the top end) if you mean by the end of the year.  Even the third party exclusives haven't reached the bottom end of that range yet.  They could leg it out to those numbers eventually, but what it has sold after a few years might not factor into any publisher decisions.  The other problem is that all the games you mentioned are western focused and the Wii U doesn't seem to be showing many signs of life in Europe.

500k-700k this year.

No 3rd party titles are reaching 1m when the system only has a userbase of 3m.

In terms of actually making money back, anything over 100k will net them profit I'm guessing.

Depends on how much porting costs.

Numbers will never be ass good as the counterparts.

Above 500k, that's for sure.

But I'd say that for some games they will want an attach rate of about 15-20% of the userbase to call them successful (that's the rate for some games on the PS360).