I imagine there are a lot of reasons. Some are more emotion based, others on more concrete concerns. There are people that are still upset about ME3's ending, for example, while others note that the original DA and ME writers/creators are gone, and wonder what things will be like. The delays have some worried, others dislike the writing direction the DA team went with Inquisition, and project it onto the ME series, regardless of whether they should. Many reasons, many lack of reasons, too many to list.
None of them are really right, or wrong, and I think, in the end, most people just want Andromeda to be a great game. I don't really know anyone that goes into a new game hoping it will be terrible and frustrating. I'd like to think the concern over Andromeda that some voice is all about how badly the people involved want this to be a great new experience.
As for faith, I don't really know what you think faith has to do with this situation. Faith isn't something you should have in a game or developer. Hopes, concerns, expectations, worries, all sorts of things, sure, but faith? Having faith doesn't make a game good anymore than it would make it bad, and the same goes for developers, having faith in their goodness or lack thereof is rather silly. I don't know about anyone else here, but I give compliments when they're earned, and in no other situation.
It does seem, from the outside looking in, and through no other means, that Bioware are having a bit of trouble getting ME:A out. That's not immediately a bad thing, anymore than it is a good thing, with any luck whatever challenges ME:A represents to the team will result in them rising to the occasion, knocking it out of the park.
I think that's something we'd all like to see, but it's not a given. They either will or the won't. That's a story only time will tell.