I'm dating you wrap it up when the creative team days "done" which is what I believe ND have stayed.While I agree with you on principal isn't Uncharted 4 an example of what a studio can do to continue a franchise that has 'stopped on a high'? Didn't U3 both wrap up the franchise and become a critical success?
I'm not saying Halo 5 has done this. I'm as disappointed in it's campaign as others are. But saying that you should end a hugely successful franchise just because it has had it's original trilogy wrapped up simply doesn't make sense, especially in light of this news.
Halo is an example of a franchise continuing past that point for commercial reasons only with a new creative team in place just to keep it going.
That almost always leads to dinishing returns.
Hence if ND are saying "done" I'm saying then leave it don't assign s new team just to carry it on until it's milked dry.