I did enjoy most of the campaign, although the "final boss" was a bit dry. Halo 5 has been said to be the darkest Halo to date, so I'm hoping we'll see some intense Flood action with next gen graphics.
I'm ****ing stoked for Halo 5 --- The mind of the subject will desperately struggle to create memories where none exist... ~~FREE SHERIDAN~~
Halo 4 - Start of the new trilogy which will focus on Chief and Cortana's relationship. Goes deep into their relationship and now Chief is devastated by her death.
Halo 5 - The Didact returns to continue his domination and has captured Cortana to aid in his cause.
Halo - 6 Chief finds Halsey and she helps him save Cortana and stop the Didact before Halsey dies.
As far as boss battles go they tried that in Halo 2 and they weren't really liked. Wouldn't mind Scarab battles again though. I can see it now... Promethean Destroyers. --- http://i.imgur.com/HLzCM.gif