You say this based on what? From what they said when asked, they probably did had one
No it isn't, who do you think pushed for Sage to appear so soon in the Comic? Sega, you constantly blame the american side/IDW side of the creators and never Sega for being bad at managing and working alongside them, you are not being fair in your judgement, you have no basis that they didn't had a plan, and you equally have no basis for giving Sega the benefit of the doubt here, they had a plan, or at least an idea, on to how implement post frontiers stuff, Sega said "screw you do it now" to them and this is the result, this plus all the mandates that limit and make the stories feel rushed, it is very clear who is the most likely culprit here, you should try and be less biased towards the Japanese side, they are not the one all be all