Rising is the future canonically to the Metal Gear story line. And my biggest issue with Metal Gear Rising: Revengence (I don't think that's a real word) is how it's a Metal Gear in name only basically. Decent hack n slasher but, as a Metal Gear titles it falls flat on its a$$. It really lacks that directorial flare Kojima brings and is just "style over substance" That's not Metal Gear. Metal Gear is both.
Yes, but it's doesn't necessarily alter the MGS story; it's just a seemingly insignificant chapter. So far, it hasn't had any influence on the older games, and I don't think it'll have an impact on MGS5 or Ground Zeroes either. And I don't know, but Metal Gear hasn't existed since, what, the early '90s? It's always been Metal Gear Solid, and now that it's called Metal Gear Rising, it's basically a franchise in itself. I believe It's set in 2018, so yeah, it's canon. But is that really such an issue? Snake's story has been told, and Big Boss is still getting attention, and they're not tied to what Raiden is doing in some far-off country, in 2018, no less. In this case, I'd say it being canon really doesn't matter, especially if die-hard MGS fans hate Raiden.
Rising was just wasting time. As far as the Metal Gear crowd is concerned, The Phantom Pain is what was really on everyone's mind. That's why people didn't want Rising. They wanted the next Metal Gear Solid. The one Kojima was making himself.
And yet, they're also working on MGS5 and Ground Zeroes. Started from before they made MGR, I think. So they made a game for the people who happen to like hack and slash games. So what? It's a bonus! You've still got MGS5 and MGS: GZ, so just ignore MGR, then. Want to play MGS, then by all means, do. I'm going to buy MGR as well as MGS5 and Ground Zeroes, because I would enjoy all three - and I've played MGS2, MGS3, Peace Walker and MGS4, so I'm not a stranger to the series either. No sense in moaning about something that's basically a canon spin-off (H&S) set in the future.