Announcing a game a year in advance when you have a lot of the development already done and you have a specific advertising plan is sensible. But 2 years for franchises isn't unheard of or crazy and is really really common. Especially with franchises.
ME 4 only recently started doing trailers, sure, but it was officially announced back in June 2015, almost two years in before the game will actually release… and was unnofficially talked about by the team as far back as late 2012 when all the DLC was winding down on ME3
Zelda: BoW was announced in 2013 for a planned 2015 release and comes out in 2 months.
Dragon Quest 11 was announced in January 2016, but didn't get an official trailer annuncement until June... and we still don't have a release date for it other than "sometime this year... in Japan." Nino Kuni 2 was announced in 2015 and still has no release date except for "this year".
Games being planned and announced waaaaaay in advance is normal and not inherantly a bad thing. When its big franchise stuff, you gotta keep the shareholders happpy and give the fans something. Xenoblade for all that its huge... is still a fairly new franchise and not a whole lot rides solely on its shoulders. Its release doesn't make or break the company for that year. (Especilly in Xenoblades case where that team also co-works on ANimal Crossing, Zelda, Splatoon, etc.)
Koei doesn't announce every Dynasty Warrior game three years in advance because they do dozens of those and pump one out every 4 months in some form or another, so announcing one 8 months ahead of time or so does them fine.
So no, it's not bad or wrong for Square to announce a game 2 or 3 years in advance. The problem is they can't ocus and get things done and end up announcing 5-10 years in advance.