Ubisoft is an incredibly hit or miss company in my experience, but yeah, they definitely still can make a really good hit when they don't miss.
I think the MMO venture is an extremely dangerous market. Considering the average dev time for it is 5 years roughly by the looks of it, the costs are extremely high. Not only that but the size of the teams are also huge which means the money is going to be going out even faster. If there is no long term return on it it's a huge bomb. Take into account that MMOs are expected to have features and innovations that other games have already introduced, it's hard to implement some ideas midway through the development process. Making an MMO is an arduous this I would assume.
I think this is part of the reason why ventures like TOR and FF14 failed. They tried to capitalize on the success of something in the past or present but took too long and thought they were taking a share of the MMO market but in reality they were being further left behind. Guild Wars 2 was in development for a long time and while it did well, I think cases like these don't happen often.
We also have to take into consideration of the profit model. Do they launch F2P or P2P? If it's F2P, are microtransactions built into the design of the game or are they just tacked on. There are so many variables and unknowns, MMO developing is a huge gamble. It's a very dynamic developing niche that I think will be hard to overcome for years and quite possibly never.