You liked that Sonic DS game? I thought it was pretty lackluster.
That Sonic DS game got a lot of positive response as one of the better Sonic spin-offs ever made. So that would be a terrible example of them doing you wrong.
I think Mass Effect 2 is significantly more boring to me than Mass Effect 1 (I still haven't mustered the ability to complete it). I think Dragon Age was watered down, however I also think it was better than NWN 1 (NWN2 MOTB being an order of magnitude better than Dragon Age).
So I certainly wouldn't say Bioware is on a downward spiral, but I would say they are flailing. They are trying to branch away from a path that they know how to do very, very well. And all these efforts, while good are not dazzling in the same respect as their own familiar territory.
Bioware has the capability to make really amazing RPGs, but they do not have Blizzards quality control, that much is apparent.
None of this means that Bioware can't make a decent ME style FPS spin-off. But it does mean it is a significantly up hill battle for what? Does anyone have a desire to play an FPS based around ME? I've got access to so many FPS games that the genre is basically diluted. I love FPS and I play maybe 20% of what is released for the genre... if that. However, what is obvious is that
NO ONE is trying to make RPGs the way Bioware used to make them. That is a current, guaranteed unfilled gap. Why would you waste resources on an area of business where there is already ridiculous amounts of surplus while ignoring an area with no product at all. Sure, COD makes a lot of money, but haven't enough game developers learned that just because Activision makes money with CoD and just because Blizzard makes money with WoW that it does not mean you can make a clone and even make a fraction of that ammount.