I'm not the only one upset with how ME3 ended up. Not just about the ending. Why I want a clean break from ME1-3 plot wise. Unless they retcon part 3 as a bad dream...
I'd rather they retcon or simply ignore the **** out of 3 than continue to justify its existence with retroactive additions and apology content. That's the problem about ME:A being a continuation. I fear they'll try to make it like the Leviathan DLC but as a full game.
Regarding the Crucible... it's on the border I feel. It's introduced with a really big contrivance, but is really a MacGuffin hinting at becoming a DEM until it does become a DEM at the ending.
I've thought about it and while I really wish the Crucible would've been introduced in a less contrived way the big problem is a logistical one. If we simply discovered some artifacts and slowly learned it might be used as a superweapon we're too late into the game and the building process becomes unbelievable whereas because it's introduced so early in the game, it's easier to swallow that it gets built over the course of the plot. I do think, however they should've downplayed the "It might win the war!" idea because it's just hard to see how this device would conveniently target Reapers and be the end of the Reapers when there's so many.
They should've probably just said "It might be a huge military asset, we have to build it" but really, this is in nitpicking territory, I realize. I just wish the writing had more subtlety about it, but the execution is still decent in itself.
I don't think the Crucible ruined the game, either way. That would be the intro and ending and game-design related things that did that, but we'll see what Andromeda does with the IP.
If it tries to continue Mass Effect 3's disasterous bookend it may already lose the willing suspension of disbelief for thousands of fans, that's all I really have to say.