I think I'm one of the few who really liked the vibe from Gears 4. I'm wasn't a fan of the series before, though, and I liked that it didn't look as bro-ish.
Quantum Break might become Microsoft's Infamous but development seems very cluttered with the TV stuff so that might be a reach. It could be so story-driven that becoming a continuous franchise is impractical.
Forza is a strong brand now.
Halo 5 will probably be seen as a disappointment in general terms, which means Halo 6 (or whatever) had be very, very strong. I know Microsoft is super committed to Halo but it might be time to start searching for the next blockbuster.
It's kind of interesting that Microsoft is so invested in continuing Halo and Gears while it looks like Sony is fine with moving on from popular franchises after a certain point.
